Problem with multiple bouncing balls program in C
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I am afraid that information tells us nothing. You need to run your code in the debugger which will help you to find out exactly where it is stopping. But, as I already said, this library is very old and may not work under Windows.
I have seen similar projects which ran very good. Here is what it shows after the debugging: https://mega.nz/#!NRwEAJKR!KI5cTeFhAaagIaRlbBoba1ugKt1j2RYEgUkF4lc8Atc
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I have seen similar projects which ran very good. Here is what it shows after the debugging: https://mega.nz/#!NRwEAJKR!KI5cTeFhAaagIaRlbBoba1ugKt1j2RYEgUkF4lc8Atc
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You might get out of bound array accesses when
stepis always >= 0.63:total=n*7;
num=(int *) malloc(total*sizeof(int));
// ...
do
{
j=0;
for(i=0; i<=n; i++)
{
if (step >= 0.03)
{
// Possible out of bound accesses here (j >= total)
// ...
j=j+7;
}
}
}
while (!kbhit());You have to change the
forloop tofor(i=0; iI also don't understand why you are only updating when
stepis large enough. If that does not happen, balls at the end of the array will be updated less often than the initial ones.You are checking if the new ball position is outside and inverts the direction if so but are still drawing the ball when outside. A better solution might be drawing it at the border (here for x):
if (num[j]+num[j+4]>=getmaxx() || num[j]-num[j+4]<=0)
{
num[j+5] *= -1;
if (num[j]+num[j+4] > getmaxx())
num[j] = getmaxx() - num[j+4];
if (num[j]-num[j+4] < 0)
num[j] = num[j+4];
}Finally it might not work as expected because you have up to 7 balls and did not handle overlapping ones. I guess you want to detect also ball collisions which would result in no overlapping. But that is also not handled by your code.
Well, it didn't work and yes I also want to handle overlapping balls and make them bounce together and change direction. But, I don't know how. However, I don't have up to 7 balls. I actually use 3, but each of them has 7 data (color, position, speed etc.). That's why I use i at the for loop to count the number of loops (each ball). Then I use j to go to the desired data of each ball. All the data is being inserted to the program from a .txt file as you can see. It might seem stupid that I don't understand some thing. However, I am a beginner and I am trying to learn. So, please help me and be patient. I really appreciate your help.
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To tell the truth, I don't understand.
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Well, it didn't work and yes I also want to handle overlapping balls and make them bounce together and change direction. But, I don't know how. However, I don't have up to 7 balls. I actually use 3, but each of them has 7 data (color, position, speed etc.). That's why I use i at the for loop to count the number of loops (each ball). Then I use j to go to the desired data of each ball. All the data is being inserted to the program from a .txt file as you can see. It might seem stupid that I don't understand some thing. However, I am a beginner and I am trying to learn. So, please help me and be patient. I really appreciate your help.
Sorry, I missed the number of balls. But my other notes are still valid (out of bound array access and why not updating with small steps). For timing purposes (slower movement), wait outside the
forloop. I suggest to start with one ball to implement and check the border bouncing. To be realistic, the new directions should be calculated according to the collision angle. Then proceed with two balls to make it simpler. For collison detection you need another loop (runing from currently processed ball index + 1 to number of balls) to check for collisions like with the borders. Upon a collision you have to set the collision position as new position for both balls and adjust the directions (which requires a flag / state that the other ball has been already processed within the current loop execution). Again, the new directions should be calculated according to the collision angles. To check the code, you can suppress the drawing and print out the positions and changings instead. Or write them to a text file so that you can inspect it later. For testing it might be also helpful to stop after each step and continue after a key press. So you can check your calculations. -
Sorry, I missed the number of balls. But my other notes are still valid (out of bound array access and why not updating with small steps). For timing purposes (slower movement), wait outside the
forloop. I suggest to start with one ball to implement and check the border bouncing. To be realistic, the new directions should be calculated according to the collision angle. Then proceed with two balls to make it simpler. For collison detection you need another loop (runing from currently processed ball index + 1 to number of balls) to check for collisions like with the borders. Upon a collision you have to set the collision position as new position for both balls and adjust the directions (which requires a flag / state that the other ball has been already processed within the current loop execution). Again, the new directions should be calculated according to the collision angles. To check the code, you can suppress the drawing and print out the positions and changings instead. Or write them to a text file so that you can inspect it later. For testing it might be also helpful to stop after each step and continue after a key press. So you can check your calculations.I have already made it with one ball and I tried to continue with two, three etc. However, I still do something wrong with more than one balls and I can't understand what. I have been working on this for almost a month and I have tried everything. I also searched the internet and asked at other forums too, but still nothing. I only managed to make it with one ball. I understand what you say and that's what I am thinking too, but I can't put it inside code and make it run correctly.
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To tell the truth, I don't understand.
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I have already made it with one ball and I tried to continue with two, three etc. However, I still do something wrong with more than one balls and I can't understand what. I have been working on this for almost a month and I have tried everything. I also searched the internet and asked at other forums too, but still nothing. I only managed to make it with one ball. I understand what you say and that's what I am thinking too, but I can't put it inside code and make it run correctly.
Your posted code does not check for ball to ball collisions. You have to implement it. There should be examples in the net for the algorithms.
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Hello, I am trying to make a program in C with multiple bouncing balls. The problem is that I have created a code, but my program doesn’t run properly. To be more exact, I think the part where it reads the data is fine, but then there is a problem in the code of the graphics.h library. I cannot understand where the problem is, as it is the first time I use this library. Thank you in advamce. Here is my code:
#include #include #include #include #include int main()
{
FILE *input;
int n, *num, i, total, j;
if((input=fopen("data.txt", "r"))!=NULL)
{
fscanf(input, "%d", &n);
total=n*7;
num=(int *) malloc(total*sizeof(int));
if(num!=NULL)
{
for(i=0; i= 0.03)
{
previous = finish;
setfillstyle(SOLID_FILL,BLACK);
setcolor(BLACK);
fillellipse(num[j],num[j+1],num[j+4],num[j+4]);
num[j]+= num[j+5]*step;
num[j+1]+= num[j+6]*step;
if (num[j]+num[j+4]>=getmaxx() || num[j]-num[j+4]<=0)
{
num[j+5] *= -1;
}
if (num[j+1]+num[j+4]>=getmaxy() || num[j+1]-num[j+4]<=0)
{
num[j+6] *= -1;
}
setfillstyle(SOLID_FILL,RED);
setcolor(RED);
fillellipse(num[j],num[j+1],num[j+4],num[j+4]);
j=j+7;
}
}Are you trying to recreate a 30-years old xonix game? :-D :rolleyes: :laugh:
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Hello, I am trying to make a program in C with multiple bouncing balls. The problem is that I have created a code, but my program doesn’t run properly. To be more exact, I think the part where it reads the data is fine, but then there is a problem in the code of the graphics.h library. I cannot understand where the problem is, as it is the first time I use this library. Thank you in advamce. Here is my code:
#include #include #include #include #include int main()
{
FILE *input;
int n, *num, i, total, j;
if((input=fopen("data.txt", "r"))!=NULL)
{
fscanf(input, "%d", &n);
total=n*7;
num=(int *) malloc(total*sizeof(int));
if(num!=NULL)
{
for(i=0; i= 0.03)
{
previous = finish;
setfillstyle(SOLID_FILL,BLACK);
setcolor(BLACK);
fillellipse(num[j],num[j+1],num[j+4],num[j+4]);
num[j]+= num[j+5]*step;
num[j+1]+= num[j+6]*step;
if (num[j]+num[j+4]>=getmaxx() || num[j]-num[j+4]<=0)
{
num[j+5] *= -1;
}
if (num[j+1]+num[j+4]>=getmaxy() || num[j+1]-num[j+4]<=0)
{
num[j+6] *= -1;
}
setfillstyle(SOLID_FILL,RED);
setcolor(RED);
fillellipse(num[j],num[j+1],num[j+4],num[j+4]);
j=j+7;
}
}