Thread: sscanf extracts same wrong integers every time

Good day C Gurus

I m trying to insert the list of the name surnames ID and grades of 5 students and then exctrating their grades using sscanf my code is the folowing

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>






int main()
{


    char matrix[5][35];
  char name[5][10];
  char surname[5][10];
  int IDE[5][6]={0};
/* i intilized all the int array to 0 to avoid them be filled with garbage*/
  int mark[5][3]={0};
  int average =0;
  int i;int cnt; int flag[5]={0};
  for (i=0;i<5;i++)
  {
      gets(matrix[i]);
  }








  for (i=0;i<5;i++)
  {
  sscanf(matrix[i],"%s %s %d %d",name[i],surname[i],&IDE[i],&mark[i]);
  }


   for (i=0;i<5;i++)
  {
  printf("%s %s %d %d",name[i],surname[i],IDE[i],mark[i]);
  }

the printf part is only to check my data and i was surprised to see that sscanf gave me every time same wrong values for integers

what s wrong with me and how can i adress it?

Many thanks in advance

You should make sure your code is formatted and indented properly, and nothing is cut out (you're missing a closing brace).

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
 
int main()
{
    char matrix[5][35];
    char name[5][10];
    char surname[5][10];
    int IDE[5][6]={0};
    
    int mark[5][3]={0};
    int average =0;
    int i;
    int cnt;
    int flag[5]={0};
  
    for (i=0;i<5;i++)
    {
          fgets(matrix[i], 35, stdin);
    }

    for (i=0;i<5;i++)
    {
        sscanf(matrix[i],"%s %s %d %d",name[i],surname[i],&IDE[i],&mark[i]);
    }
 
    for (i=0;i<5;i++)
    {
        printf("%s %s %d %d",name[i],surname[i],IDE[i],mark[i]);
    }
    
    return 0;
}

Notice I took the courtesy of replacing gets() with fgets(), since gets() is dangerous and obsolete.

Then make sure you are compiling with full warnings:

$ gcc cboard.c -Wall -Wextra
cboard.c: In function ‘main’:
cboard.c:11:5: warning: missing braces around initializer [-Wmissing-braces]
cboard.c:11:5: warning: (near initialization for ‘IDE[0]’) [-Wmissing-braces]
cboard.c:13:5: warning: missing braces around initializer [-Wmissing-braces]
cboard.c:13:5: warning: (near initialization for ‘mark[0]’) [-Wmissing-braces]
cboard.c:26:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 5 has type ‘int (*)[6]’ [-Wformat]
cboard.c:26:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 6 has type ‘int (*)[3]’ [-Wformat]
cboard.c:31:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘int *’ [-Wformat]
cboard.c:31:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 5 has type ‘int *’ [-Wformat]
cboard.c:17:9: warning: unused variable ‘flag’ [-Wunused-variable]
cboard.c:16:9: warning: unused variable ‘cnt’ [-Wunused-variable]
cboard.c:14:9: warning: unused variable ‘average’ [-Wunused-variable]

The middle warnings about "format '%d' ..." are the problem. "IDE" and "mark" are two-dimensional arrays, but you are trying to use them as if they were one-dimensional arrays.

Thank you Matticus for your prompt reply and I could fix the problem following your remarks

Code:

sscanf(matrix[i],"%s %s %d %d",name[i],surname[i],&IDE[i][1],&mark[i][1]);

you said that IDE and mark are two dimensional arrays


int mark[5][3]
IDE[5][6]
so first here are my questions

• How can C make the difference between char matrix[5][8] to indicate 5 rows 8 colomns and char matrix[5][8] that means that matrix has 5 rows and one colonne with the size of 8 for each row (same if the matrix of type integer)????
• you also said that ""IDE" and "mark" are two-dimensional arrays, but you are trying to use them as if they were one-dimensional arrays" but still this problem didn t happen with the char variable used in the same code ligne why is that?

Thanks a million!!!








int mark[5][3]
IDE[5][6]