Thread: Debugging help :(

Don;t think my idea are gonna help somehow I tried it and got compilation errors

OK so I change it back apart from he argv thing and it seems to work.

OK I compiled it and it ran OK.

This code works
I moved the malloc inside the loop

Code:

#include <stdio.h>
#include <math.h>
#include <conio.h>
 
 
typedef double real;
 
 
typedef struct
{
    real xpos;
    real ypos;
    real zpos;
     
    real uvel;
    real vvel;
    real wvel;
     
    real omegax;
    real omegay;
    real omegaz;
     
    real radius;
    real mass;
     
} sphere;
 
 
void update_position(sphere *ball, real dt)
{
   //(*ball).xpos
   ball->xpos=ball->xpos + dt*ball->vvel;
   //ypos,zpos  
}
 
 
void detect_ball(sphere *ball1, sphere *ball2, real *pdist)
{
     
    *pdist=sqrt((ball2->xpos-ball1->xpos)*(ball2->xpos-ball1->xpos)+
               (ball2->ypos-ball1->ypos)*(ball2->ypos-ball1->ypos));
                
//        if ( dist<= (ball1->radius + ball2->radius) +0.0075 )
//        {
//            if ( dist>= ball1->radius + ball2->radius -0.0075   )
//            {  
//            *ptime=0;
//            }
//        }
 
 
}
 
 
int main(int argc, char *argv)
{
    real dt=0.01;
    real t, dist1, tmax=1, mlimit, firstvvel, gap=1.5,  dist[2], ballmatxpos[101][2];
    int nballs=1 ;
    int i,j,m,k;
    sphere *ball;
      
  
    mlimit=tmax/dt;
    //initialise positions
    for(i=0;i<=nballs;i++)
    {
 
ball=(sphere *)malloc(nballs*sizeof(sphere));
       ball[i].radius=0.5;
         ball[i].ypos=0.0;  
       ball[i].ypos=0.0; 
        
       ball[i].uvel=1.0;
       ball[0].vvel=1.0;
       ball[1].vvel=0.0;
    }
     
    //pendulum to be released
   // ball[0].xpos=0;
    //ball[0].ypos=0;
  //  firstvvel=0;
     
    //timestep loop
    t=0.0;
    dist1=0.0;
    while(t<tmax)
    {
        for(m=0;m<=mlimit;m++)
       {
       //update position
        for(i=0;i<=nballs;i++)
        {
              update_position(&(ball[i]), dt); 
        }
       //collision detection
        for(i=0;i<=nballs;i++)
        {
            for(j=0;j<=nballs;j++)
            {
                detect_ball(&(ball[i]),&(ball[j]), &dist1);     
                              
              if ( dist1 <= (ball[i].radius + ball[j].radius) +0.075 )
                {
                   if ( dist1 >= (ball[i].radius + ball[j].radius) -0.075   )
                    {
             //  ball2->uvel=ball1->vvel;
                //yes collision, modify velocities and rotation rates  
                    t=0;
                     }
                }
            }
        }
         
        ballmatxpos[m][0]=t;
        ballmatxpos[m][1]=ball[0].xpos;
 
 
   printf("In this case, initial velocity= %3.4lf with t=%3.4lf \n", ballmatxpos[m][0], t );  
                                
        t+=dt;   
        }
    }
     
 
 
//    ---------------//-------------------------
      FILE *pFile1;
         FILE *pFile2;
         pFile1 = fopen("graphing3.txt", "w");
         pFile2 = fopen("graphing4.txt", "w");
         if (pFile1 != NULL)
        {
             for(m=0;m<=mlimit;m++)
             {
         fprintf( pFile1, " %3.4lf \n ", ballmatxpos[m][0]);
              }
      fprintf( pFile1,"\n");
      fclose(pFile1);
        }
      if (pFile2 != NULL)
        {
             for(m=0;m<=mlimit;m++)
             {
         fprintf( pFile2, " %3.4lf  \n", ballmatxpos[m][1]);
         }
       fprintf( pFile2,"\n");
      fclose(pFile2);     
       } 
                 else
        {
            printf("inda dapat print bro");
       }
 
 
 
 
 
 
//  ----------------------------------------------------- 
 
 
 
 
     
    getch();
    return 0;
}

Originally Posted by esbo

This code works
I moved the malloc inside the loop

Stop hijacking/spamming this thread with one sentence replies. Your code doesn't work, or at least, you introduced a big memory leak by doing so. As I said, the declaration and malloc call were fine, just the loop did one too many iterations.

This line causes a problem I accidental change it from

Code:

ball[i].xpos=(real) i * (2*ball[i].radius + gap);

to

Code:

ball[i].ypos=0.0;

OK I said y not x but the issue is in the line I mention so it seems.

Originally Posted by anduril462

Stop hijacking/spamming this thread with one sentence replies. Your code doesn't work, or at least, you introduced a big memory leak by doing so. As I said, the declaration and malloc call were fine, just the loop did one too many iterations.

The code I posted runs OK, if providing a solution or a partial solution or something helpful counts a 'hijacking then I guess I am guilty.

The code I posted runs OK

I ran it and got a segmentation fault.

Furthermore, the spamming comment was in reference to posting multiple times in a row, all within a few minutes of each other. We're already halfway down the second page of this thread, and it shouldn't be that long. There's no reason you couldn't have added further comments to your previous posts with an edit.

Actually, it was earlier today I stumbled upon the famous "pointer" thread by said poster. I was trying to find it again, but to no avail.

Code:

#include <stdio.h>
#include <math.h>
#include <conio.h>
  
  
typedef double real;
  
  
typedef struct
{
    real xpos;
    real ypos;
    real zpos;
      
    real uvel;
    real vvel;
    real wvel;
      
    real omegax;
    real omegay;
    real omegaz;
      
    real radius;
    real mass;
      
} sphere;
  
  
void update_position(sphere *ball, real dt)
{
   //(*ball).xpos
   ball->xpos=ball->xpos + dt*ball->vvel;
   //ypos,zpos 
}
  
  
void detect_ball(sphere *ball1, sphere *ball2, real *pdist)
{
      
    *pdist=sqrt((ball2->xpos-ball1->xpos)*(ball2->xpos-ball1->xpos)+
               (ball2->ypos-ball1->ypos)*(ball2->ypos-ball1->ypos));
                 
//        if ( dist<= (ball1->radius + ball2->radius) +0.0075 )
//        {
//            if ( dist>= ball1->radius + ball2->radius -0.0075   )
//            { 
//            *ptime=0;
//            }
//        }
  
  
}
  
  
int main(int argc, char *argv)
{
    real dt=0.01;
    real t, dist1, tmax=1, mlimit, firstvvel, gap=1.5,  dist[2], ballmatxpos[101][2];
    int nballs=1 ;
    int i,j,m,k;
    sphere *ball;
       
   
    mlimit=tmax/dt;
    //initialise positions
    for(i=0;i<=nballs;i++)
    {
  
ball=(sphere *)malloc(nballs*sizeof(sphere));
       ball[i].radius=0.5;
//         ball[i].ypos=0.0; 
  //      ball[i].xpos=(real) i * (2*ball[i].radius + gap);

//		ball[i].xpos=(real) i * (2*ball[i].radius + gap);
      ball[i].xpos=0.0;
       ball[i].ypos=0.0;
         



       ball[i].uvel=1.0;
       ball[0].vvel=1.0;
       ball[1].vvel=0.0;
    }
      
    //pendulum to be released
   // ball[0].xpos=0;
    //ball[0].ypos=0;
  //  firstvvel=0;
      
    //timestep loop
    t=0.0;
    dist1=0.0;
    while(t<tmax)
    {
        for(m=0;m<=mlimit;m++)
       {
       //update position
        for(i=0;i<=nballs;i++)
        {
              update_position(&(ball[i]), dt);
        }
       //collision detection
        for(i=0;i<=nballs;i++)
        {
            for(j=0;j<=nballs;j++)
            {
                detect_ball(&(ball[i]),&(ball[j]), &dist1);    
                               
              if ( dist1 <= (ball[i].radius + ball[j].radius) +0.075 )
                {
                   if ( dist1 >= (ball[i].radius + ball[j].radius) -0.075   )
                    {
             //  ball2->uvel=ball1->vvel;
                //yes collision, modify velocities and rotation rates 
                    t=0;
                     }
                }
            }
        }
          
        ballmatxpos[m][0]=t;
        ballmatxpos[m][1]=ball[0].xpos;
  
  
   printf("In this case, initial velocity= %3.4lf with t=%3.4lf \n", ballmatxpos[m][0], t ); 
                                 
        t+=dt;  
        }
    }
      
  
  
//    ---------------//-------------------------
      FILE *pFile1;
         FILE *pFile2;
         pFile1 = fopen("graphing3.txt", "w");
         pFile2 = fopen("graphing4.txt", "w");
         if (pFile1 != NULL)
        {
             for(m=0;m<=mlimit;m++)
             {
         fprintf( pFile1, " %3.4lf \n ", ballmatxpos[m][0]);
              }
      fprintf( pFile1,"\n");
      fclose(pFile1);
        }
      if (pFile2 != NULL)
        {
             for(m=0;m<=mlimit;m++)
             {
         fprintf( pFile2, " %3.4lf  \n", ballmatxpos[m][1]);
         }
       fprintf( pFile2,"\n");
      fclose(pFile2);    
       }
                 else
        {
            printf("inda dapat print bro");
       }
  
  
  
  
  
  
//  -----------------------------------------------------
  
  
  
  
      
    getch();
    return 0;
}

The above code works I changed this line

Code:

//		ball[i].xpos=(real) i * (2*ball[i].radius + gap);
      ball[i].xpos=0.0;

Worked on my machine anyway so an issue with that line in some way.


It produced two files with data in anyway
graphing4.txt

Code:

 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN  
 NaN

graphing3.txt

Code:

0.0000 
  0.0100 
  0.0200 
  0.0300 
  0.0400 
  0.0500 
  0.0600 
  0.0700 
  0.0800 
  0.0900 
  0.1000 
  0.1100 
  0.1200 
  0.1300 
  0.1400 
  0.1500 
  0.1600 
  0.1700 
  0.1800 
  0.1900 
  0.2000 
  0.2100 
  0.2200 
  0.2300 
  0.2400 
  0.2500 
  0.2600 
  0.2700 
  0.2800 
  0.2900 
  0.3000 
  0.3100 
  0.3200 
  0.3300 
  0.3400 
  0.3500

Originally Posted by anduril462

Then how do you explain your post #14? Nothing constructive there, so why say it? For that matter, posts 11-14 and 16-18 are basically you just thinking "out loud" on the forum, and post #11 is more likely to confuse somebody than help, with you just throwing around random syntax. Take the time to gather your thoughts, try out your ideas and make one meaningful post. All those little, one sentence, non-constructive posts just help derail the thread faster. That may be a matter of opinion, but I would wager a fair sum of money that it is an opinion agreed upon by the majority of the forum regulars.

Furthermore, Matticus' seg fault statement, at least, is not an opinion, but a pure fact. It is also a sign that your code definitely does not work. Again, test your code thoroughly before

We're not trying to be a-holes about this, we're just trying to keep the thread more on track of the OP's actual problem, instead of a thread for you to write your thoughts out as they happen.

Yes, this post is itself off-topic, but hopefully explains where we are coming from enough that we can all just drop this side-issue and return to helping people with programming, hopefully in a more productive manner.

I provided code which produced the files he required, somewhat more than what you have managed.

I don't know why Matticus got a segmentation fault, perhaps he made an error.