Problem using strings

Rodrigo Lourenco

I'm trying to change a given string in a function, but I send a string, try to change it directly and get a core dump, so I tried to create a string in the function, but it doesn't send the correct string. This function must eliminate all Capital letter's it's a simple one, but I am making a mistake and don't see where. Can any one help me please.

#include #include #include #include #define false 1
#define true 0

char* my_strdelupper(char* s){

  int i,j, len;
  char aux\[100\];
  char debuging;

  len = strlen(s);
  j = 0;
  for (i = 0; \*(s + i) != '\\0' < len; i++){
      if (!isupper(\*(s+i))){
          printf("%c",\*(s+i));
          debuging = \*(s + i);
          \*(aux + j) = debuging;
         j++;
      }
  }
  \*(aux + j) = '\\0';
  printf("\\n");
  puts(aux);

  return strcpy(aux, aux);

}

int main()
{
char *s3="Quem quer casar com um programador?";
printf("%s\n",my_strdelupper(s3)); /* aria, sabes que é s o meu "rande mor " */

return 0;
}

Victor Nijegorodov

Why not using the std::string with all its and other std methods? :zzz: :confused:

k5054

You have: char *s3 = "...". Although s3 is declared as char * the type of the string is const char *. Use char s3[] = "..." instead.

David Crow

If I were to hazard a guess, I'd say it has to do with aux being destroyed (i.e., going out of scope) once my_strdelupper() returns.

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Joe Woodbury

This line of code puzzles me:

*(s + i) != '\0' < len

It probably should be:

i < len

A second problem is that you are doing the copy only on !isupper, when you should be doing it always as soon as an uppercase character is detected. A third problem is the strcpy() at the end. It's pointless. A fourth problem is that you are returning a pointer to the a stack value which becomes invalid because the call to printf is likely overwriting it and is likely causing a fault.

Lost User

Try this:

char* my_strdelupper(char* s){
int i, len;
char* sl;

len = strlen(s);
sl = (char\*)malloc(len+1); // space for the converted string
i = 0; // index to the converted string buffer
while (\*s != '\\0'){
    if (!isupper(\*s)){
        sl\[i++\] = \*s; // copy lower case letters
    }
    s++;
}
sl\[i\] = '\\0';
printf("%s\\n", sl);

return sl;

}

Rodrigo Lourenco

I'm working with C

Rodrigo Lourenco

You are correct, that was one mistake, but it should be *(s + i) != '\0' because I am searching for the end of line.

Rodrigo Lourenco

The stupid thing is that I can't use malloc, so I made a char array with fixed size to overcame that problem.

Rodrigo Lourenco

I think you are correct, but I tried to copy aux to s and didn't work, now I changed the code to send an array, them befour I leave I copy using srtcpy aux to s, and it's working.

Rodrigo Lourenco

It worked thanks

Rodrigo Lourenco

Thank you, for all, it was a great help. The problem was solved by:

#include #include #include #include #define false 1
#define true 0

char* my_strdelupper(char* s){

  int i,j, len;
  char aux\[100\];
  char debuging;

  len = strlen(s);
  j = 0;
  for (i = 0; \*(s + i) != '\\0'; i++){
      if (!isupper(\*(s+i))){
          debuging = \*(s + i);
          \*(aux + j) = debuging;
         j++;
      }
  }
  \*(aux + j) = '\\0';

  strcpy(s, aux);
  return s;

}

int main()
{
char s3[]="Maria, TU sabes que TU éS o meu \"Grande Amor\"";
printf("%s\n",my_strdelupper(&s3[0])); /* aria, sabes que é s o meu "rande mor " */

return 0;
}

jschell

As a note - you define 'len' but you don't use it. Presumably the assignment does not say otherwise, using that would make your code simpler.

CPallini

Note you don't need extra storage, the function may change the string in place:

char * remove_upper( char * s)
{
char * p, *q;

for (p = q = s; *p != '\0'; ++p)
if ( ! isupper(*p) )
*q++ = *p;

*q = '\0';
return s;
}

Peter_in_2780

Taken from K&R 1st ed? Certainly has that feel> :laugh: ;P

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

CPallini

It is the Wonderful C programming language, of course has such a feel. In any case, were Dennis and Brian the ones who plagiarized my programs. :-D

Member_14494321

As I have not clear idea about the std but yes this library used in most of the cases. [Fixed] Dell Printer Error 016 302 | Error Code 0x[^] helped me to get the solution.

John R Shaw

I was begging to think no one here was thinking. Thanks

INTP "Program testing can be used to show the presence of bugs, but never to show their absence." - Edsger Dijkstra "I have never been lost, but I will admit to being confused for several weeks. " - Daniel Boone