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  4. While loop not working on C.

While loop not working on C.

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data-structures
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  • T Tarun Jha

    In this program i have tried to store all the input in the array. The while should continue till the user input 0, but the loop exits only after one input.

    #include
    #include

    int main(){

    int num\[50\], i, j;
    int count = 0;
    
    printf("Enter your integer: \\n");
    
    do{
    	scanf(" %d", &num\[i\]);
    	i++;
    	count++;
    	
    }while(num\[i\]!=0);
    
    for(j=1; j<= count; j++){
    	
    	if(num\[1\] > num\[j\]){
    		num\[1\] = num\[j\];
    	}
    }
    
    printf("%d is the greatest of them all !", num\[0\]);
    
    return 0;
    

    }

    L Offline
    L Offline
    Lost User
    wrote on last edited by
    #2

    After entering the first digit you increment i to the next empty cell in the num array. So when you get to the end of the block the expression while(num[i]!=0); is false, and the loop ends. This may not always be the case with an array that is not initialised. You should check the number at the time that it is entered and exit when that is zero.

    T 1 Reply Last reply
    0
    • L Lost User

      After entering the first digit you increment i to the next empty cell in the num array. So when you get to the end of the block the expression while(num[i]!=0); is false, and the loop ends. This may not always be the case with an array that is not initialised. You should check the number at the time that it is entered and exit when that is zero.

      T Offline
      T Offline
      Tarun Jha
      wrote on last edited by
      #3

      can you write the correct code. please!

      L G 2 Replies Last reply
      0
      • T Tarun Jha

        can you write the correct code. please!

        L Offline
        L Offline
        Lost User
        wrote on last edited by
        #4

        I have explained what you need to do, and where to do it. Please try for yourself, you will learn so much more.

        T 1 Reply Last reply
        0
        • L Lost User

          I have explained what you need to do, and where to do it. Please try for yourself, you will learn so much more.

          T Offline
          T Offline
          Tarun Jha
          wrote on last edited by
          #5

          Did it. Thank you.

          1 Reply Last reply
          0
          • T Tarun Jha

            In this program i have tried to store all the input in the array. The while should continue till the user input 0, but the loop exits only after one input.

            #include
            #include

            int main(){

            int num\[50\], i, j;
            int count = 0;
            
            printf("Enter your integer: \\n");
            
            do{
            	scanf(" %d", &num\[i\]);
            	i++;
            	count++;
            	
            }while(num\[i\]!=0);
            
            for(j=1; j<= count; j++){
            	
            	if(num\[1\] > num\[j\]){
            		num\[1\] = num\[j\];
            	}
            }
            
            printf("%d is the greatest of them all !", num\[0\]);
            
            return 0;
            

            }

            _ Offline
            _ Offline
            _Superman_
            wrote on last edited by
            #6

            One more thing that I would like to add is that you should initialize variable i to 0.

            «_Superman_»  _I love work. It gives me something to do between weekends.

            _Microsoft MVP (Visual C++) (October 2009 - September 2013)

            Polymorphism in C

            T 1 Reply Last reply
            0
            • _ _Superman_

              One more thing that I would like to add is that you should initialize variable i to 0.

              «_Superman_»  _I love work. It gives me something to do between weekends.

              _Microsoft MVP (Visual C++) (October 2009 - September 2013)

              Polymorphism in C

              T Offline
              T Offline
              Tarun Jha
              wrote on last edited by
              #7

              thank you

              1 Reply Last reply
              0
              • T Tarun Jha

                In this program i have tried to store all the input in the array. The while should continue till the user input 0, but the loop exits only after one input.

                #include
                #include

                int main(){

                int num\[50\], i, j;
                int count = 0;
                
                printf("Enter your integer: \\n");
                
                do{
                	scanf(" %d", &num\[i\]);
                	i++;
                	count++;
                	
                }while(num\[i\]!=0);
                
                for(j=1; j<= count; j++){
                	
                	if(num\[1\] > num\[j\]){
                		num\[1\] = num\[j\];
                	}
                }
                
                printf("%d is the greatest of them all !", num\[0\]);
                
                return 0;
                

                }

                T Offline
                T Offline
                Tarun Jha
                wrote on last edited by
                #8

                THE WORKING CODE

                Quote:

                #include #include int main(){ int num[50], i=0, j; int count = 0; printf("Enter your integer: \n"); do{ scanf(" %d", &num[i]); i++; count++; }while(num[i-1]!=0); for(j=1; j<= count-1; j++){ if(num[0] < num[j]){ num[0] = num[j]; } } printf("%d is the greatest of them all !", num[0]); return 0; }

                D G 2 Replies Last reply
                0
                • T Tarun Jha

                  THE WORKING CODE

                  Quote:

                  #include #include int main(){ int num[50], i=0, j; int count = 0; printf("Enter your integer: \n"); do{ scanf(" %d", &num[i]); i++; count++; }while(num[i-1]!=0); for(j=1; j<= count-1; j++){ if(num[0] < num[j]){ num[0] = num[j]; } } printf("%d is the greatest of them all !", num[0]); return 0; }

                  D Offline
                  D Offline
                  David Crow
                  wrote on last edited by
                  #9

                  Suggestions: 1) The variable count is not necessary. You can use i instead. 2) The separate for() loop is not necessary. You can do the min/max checking in the while() loop.

                  "One man's wage rise is another man's price increase." - Harold Wilson

                  "Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

                  "You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

                  1 Reply Last reply
                  0
                  • T Tarun Jha

                    In this program i have tried to store all the input in the array. The while should continue till the user input 0, but the loop exits only after one input.

                    #include
                    #include

                    int main(){

                    int num\[50\], i, j;
                    int count = 0;
                    
                    printf("Enter your integer: \\n");
                    
                    do{
                    	scanf(" %d", &num\[i\]);
                    	i++;
                    	count++;
                    	
                    }while(num\[i\]!=0);
                    
                    for(j=1; j<= count; j++){
                    	
                    	if(num\[1\] > num\[j\]){
                    		num\[1\] = num\[j\];
                    	}
                    }
                    
                    printf("%d is the greatest of them all !", num\[0\]);
                    
                    return 0;
                    

                    }

                    M Offline
                    M Offline
                    Manish K Agarwal
                    wrote on last edited by
                    #10

                    here you go

                    #include
                    #include

                    int main(){

                    int num\[50\], i = -1, j;
                    int count = 0;
                    
                    printf("Enter your integer: \\n");
                    
                    do{
                    	scanf(" %d", &num\[i+1\]);
                    	i++;
                    	count++;
                    	
                    }while(num\[i\]!=0);
                    
                    for(j=1; j<= count; j++){
                    	
                    	if(num\[1\] > num\[j\]){
                    		num\[1\] = num\[j\];
                    	}
                    }
                    
                    printf("%d is the greatest of them all !", num\[0\]);
                    
                    return 0;
                    

                    }

                    T D 2 Replies Last reply
                    0
                    • T Tarun Jha

                      In this program i have tried to store all the input in the array. The while should continue till the user input 0, but the loop exits only after one input.

                      #include
                      #include

                      int main(){

                      int num\[50\], i, j;
                      int count = 0;
                      
                      printf("Enter your integer: \\n");
                      
                      do{
                      	scanf(" %d", &num\[i\]);
                      	i++;
                      	count++;
                      	
                      }while(num\[i\]!=0);
                      
                      for(j=1; j<= count; j++){
                      	
                      	if(num\[1\] > num\[j\]){
                      		num\[1\] = num\[j\];
                      	}
                      }
                      
                      printf("%d is the greatest of them all !", num\[0\]);
                      
                      return 0;
                      

                      }

                      A Offline
                      A Offline
                      asa76
                      wrote on last edited by
                      #11

                      The first problem is that the variable i has not been initialized. The second problem is that you are checking the wrong array index. See the comments in the modified version of your code below.

                      #include #include int main(){

                      int num\[50\], i, j;
                      int count = 0;
                      
                      i = 0;  // Added this
                      printf("Enter your integer: \\n");
                      
                      do{
                      	scanf(" %d", &num\[i\]);
                      	count++;
                      	
                      }while(num\[i++\]!=0);  // Changed this
                      
                      for(j=1; j<= count; j++){
                      	
                      	if(num\[1\] > num\[j\]){
                      		num\[1\] = num\[j\];
                      	}
                      }
                      
                      printf("%d is the greatest of them all !", num\[0\]);
                      
                      return 0;
                      

                      }

                      D 1 Reply Last reply
                      0
                      • T Tarun Jha

                        can you write the correct code. please!

                        G Offline
                        G Offline
                        geodoom
                        wrote on last edited by
                        #12

                        First suspicious point : you declare i but you do not initialize it (you also declare j but at least you plan to initialize it in the for loop so it is acceptable). Second suspicious point: you are to hasty to increment i. If you want to insist using a

                        do {
                        ...
                        } while (condition)

                        loop , and not a

                        while (condition)
                        { ... }

                        then you must realize that you need to check the value just read (if it was zero) and then , if it not 0 , meaning the user want to keep giving values , increase i++ , getting ready for reading the next element. Try to implement those 2 points , and also as an extra exercise , implement the while(condition) { ... } It is not hard, you can do it in around half an hour or less, and you will benefit a lot by pondering on how it will differ from your do { ... } while(condition)

                        T 1 Reply Last reply
                        0
                        • A asa76

                          The first problem is that the variable i has not been initialized. The second problem is that you are checking the wrong array index. See the comments in the modified version of your code below.

                          #include #include int main(){

                          int num\[50\], i, j;
                          int count = 0;
                          
                          i = 0;  // Added this
                          printf("Enter your integer: \\n");
                          
                          do{
                          	scanf(" %d", &num\[i\]);
                          	count++;
                          	
                          }while(num\[i++\]!=0);  // Changed this
                          
                          for(j=1; j<= count; j++){
                          	
                          	if(num\[1\] > num\[j\]){
                          		num\[1\] = num\[j\];
                          	}
                          }
                          
                          printf("%d is the greatest of them all !", num\[0\]);
                          
                          return 0;
                          

                          }

                          D Offline
                          D Offline
                          David Crow
                          wrote on last edited by
                          #13

                          asa76 wrote:

                          for(j=1; j<= count; j++)
                          {
                          if (num[1] > num[j])
                          {
                          num[1] = num[j];
                          }
                          }

                          printf("%d is the greatest of them all !", num[0]);

                          You do realize this is wrong, don't you?

                          "One man's wage rise is another man's price increase." - Harold Wilson

                          "Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

                          "You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

                          1 Reply Last reply
                          0
                          • G geodoom

                            First suspicious point : you declare i but you do not initialize it (you also declare j but at least you plan to initialize it in the for loop so it is acceptable). Second suspicious point: you are to hasty to increment i. If you want to insist using a

                            do {
                            ...
                            } while (condition)

                            loop , and not a

                            while (condition)
                            { ... }

                            then you must realize that you need to check the value just read (if it was zero) and then , if it not 0 , meaning the user want to keep giving values , increase i++ , getting ready for reading the next element. Try to implement those 2 points , and also as an extra exercise , implement the while(condition) { ... } It is not hard, you can do it in around half an hour or less, and you will benefit a lot by pondering on how it will differ from your do { ... } while(condition)

                            T Offline
                            T Offline
                            Tarun Jha
                            wrote on last edited by
                            #14

                            i will try. thank you

                            1 Reply Last reply
                            0
                            • M Manish K Agarwal

                              here you go

                              #include
                              #include

                              int main(){

                              int num\[50\], i = -1, j;
                              int count = 0;
                              
                              printf("Enter your integer: \\n");
                              
                              do{
                              	scanf(" %d", &num\[i+1\]);
                              	i++;
                              	count++;
                              	
                              }while(num\[i\]!=0);
                              
                              for(j=1; j<= count; j++){
                              	
                              	if(num\[1\] > num\[j\]){
                              		num\[1\] = num\[j\];
                              	}
                              }
                              
                              printf("%d is the greatest of them all !", num\[0\]);
                              
                              return 0;
                              

                              }

                              T Offline
                              T Offline
                              Tarun Jha
                              wrote on last edited by
                              #15

                              thank you.

                              1 Reply Last reply
                              0
                              • T Tarun Jha

                                THE WORKING CODE

                                Quote:

                                #include #include int main(){ int num[50], i=0, j; int count = 0; printf("Enter your integer: \n"); do{ scanf(" %d", &num[i]); i++; count++; }while(num[i-1]!=0); for(j=1; j<= count-1; j++){ if(num[0] < num[j]){ num[0] = num[j]; } } printf("%d is the greatest of them all !", num[0]); return 0; }

                                G Offline
                                G Offline
                                geodoom
                                wrote on last edited by
                                #16

                                Since you present a working solution you deserve to receive some more elegant alternatives. Here is how I improved your code , there are some nice tricks for you to learn from it

                                #include
                                #define SIZE 15
                                int main()
                                {
                                int num[SIZE], i=0 , max;
                                int count = 0; // be sure that we do not read more than 15 elements
                                printf("Enter your integers seperated by Enter (give 0 to finish input): \n");
                                /*
                                scanf(" %d", &num[i]);
                                while (num[i]!=0 && count < SIZE )
                                {
                                ++count;
                                scanf(" %d", &num[++i]);
                                }
                                */
                                /* Either the above while loop */
                                do{
                                scanf(" %d", &num[i]);
                                count++;
                                } while(num[i++]!=0 && count < SIZE);
                                /* Or the above do { } while loop */
                                max = num[0]; /* Avoid to altert any of your array elements */
                                for(i=1; i< count; i++)
                                if(max < num[i]) max = num[i]; /* each time we find a better max, update our max value */
                                printf("%d is the greatest of them all !\n", max);
                                return 0;
                                }

                                I have deliberately put a smaller array of 15 elements so you can test what happens if you really try to input more than 15 elements. And if you are more lazy , you can even change it to 7 elements , you only have to go to one place and do your modification now , SIZE ! Also , comment the do-while block and uncomment the while block , and compile and run again the program with various values (pay attention to provide the max at the 1st and last positions at many of your tests) . Modify everything that you do not understand ehy it is like it is [for example change the pre-increments ++i and ++count that I use , with post-increments i++ , count++ , and compile/run/test with edge cases (max given at 1st and last positions) to see what wrong things happen ].

                                T 1 Reply Last reply
                                0
                                • G geodoom

                                  Since you present a working solution you deserve to receive some more elegant alternatives. Here is how I improved your code , there are some nice tricks for you to learn from it

                                  #include
                                  #define SIZE 15
                                  int main()
                                  {
                                  int num[SIZE], i=0 , max;
                                  int count = 0; // be sure that we do not read more than 15 elements
                                  printf("Enter your integers seperated by Enter (give 0 to finish input): \n");
                                  /*
                                  scanf(" %d", &num[i]);
                                  while (num[i]!=0 && count < SIZE )
                                  {
                                  ++count;
                                  scanf(" %d", &num[++i]);
                                  }
                                  */
                                  /* Either the above while loop */
                                  do{
                                  scanf(" %d", &num[i]);
                                  count++;
                                  } while(num[i++]!=0 && count < SIZE);
                                  /* Or the above do { } while loop */
                                  max = num[0]; /* Avoid to altert any of your array elements */
                                  for(i=1; i< count; i++)
                                  if(max < num[i]) max = num[i]; /* each time we find a better max, update our max value */
                                  printf("%d is the greatest of them all !\n", max);
                                  return 0;
                                  }

                                  I have deliberately put a smaller array of 15 elements so you can test what happens if you really try to input more than 15 elements. And if you are more lazy , you can even change it to 7 elements , you only have to go to one place and do your modification now , SIZE ! Also , comment the do-while block and uncomment the while block , and compile and run again the program with various values (pay attention to provide the max at the 1st and last positions at many of your tests) . Modify everything that you do not understand ehy it is like it is [for example change the pre-increments ++i and ++count that I use , with post-increments i++ , count++ , and compile/run/test with edge cases (max given at 1st and last positions) to see what wrong things happen ].

                                  T Offline
                                  T Offline
                                  Tarun Jha
                                  wrote on last edited by
                                  #17

                                  Thank you very much.. :)

                                  1 Reply Last reply
                                  0
                                  • M Manish K Agarwal

                                    here you go

                                    #include
                                    #include

                                    int main(){

                                    int num\[50\], i = -1, j;
                                    int count = 0;
                                    
                                    printf("Enter your integer: \\n");
                                    
                                    do{
                                    	scanf(" %d", &num\[i+1\]);
                                    	i++;
                                    	count++;
                                    	
                                    }while(num\[i\]!=0);
                                    
                                    for(j=1; j<= count; j++){
                                    	
                                    	if(num\[1\] > num\[j\]){
                                    		num\[1\] = num\[j\];
                                    	}
                                    }
                                    
                                    printf("%d is the greatest of them all !", num\[0\]);
                                    
                                    return 0;
                                    

                                    }

                                    D Offline
                                    D Offline
                                    David Crow
                                    wrote on last edited by
                                    #18

                                    See here.

                                    "One man's wage rise is another man's price increase." - Harold Wilson

                                    "Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

                                    "You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

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