Thread: What's the problem with my code? [Simple C for loops and 2d int]

Hello, I'm new to C language, and I'm using Visual C as my compiler..
Here's my code:

Code:

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


    int i[8][8];
void main(){
    int row;
    int col;
   for(row=0;row<=7;row++)
    {
        for(col=0;col<=7;col++)
        {
            i[row][col]=0;
        }
    }
   printi();
 
    getchar();getchar();
}


    
int printi()
{
            char s[500];
    int row;
    int col;
    int g;
    int a=0;
       for ( row=0; row < 7; row++ ) 
       {
      for ( col=0; col < 7; col++ ) 
      {
         s[a]=("%c", (char)i[row][col] );
         a++;
      }
       }


       for(g=0;g<=sizeof(s);g++)
       {
           int a=0;
           if(a<8){
           printf("%c",s[g]);
           printf(" ");
           }
           else{
               a=0;
               printf("\n");
           }
       }
       return 0;
}

I want it to give this output:
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
But it gives me a weird set of characters that are not letters or numbers.. only weird symbols.. can u fix the code for me please and explain the problem?

Thanks in advance

Where to begin...

Code:

 s[a]=("%c", (char)i[row][col] );

This is a rather complex way to assign i_row,col as a char to s[a]. "%c" has no effect thanks to the comma operator. (Yes, the comma is an operator here.)

The crux of your problem is here:

Code:

for(g=0;g<=sizeof(s);g++)

I think if you print the value of sizeof(s) you will find it is much greater than 8x8.

This explains your results because most of the unused space in s is uninitialized. Variables are not zeroed out for you in C unless they are in global scope. (Ironic, given the scope of i). Now that you know that, please do not make all of your variables global from now on, but make sure that variables have sensible values before you use them. Using uninitialized variables leads to undefined behavior and bugs.

In the case of arrays, simply zeroing them out is sufficient.

Code:

 char s[500] = {0};

There are a couple ways to declare arrays, but if your array has a supplied size, as it does here, you do not need to supply all of the initial values; they will be zeroed out for you.

Code:

 char t[] = { 0, 0, 0, 0, 0 };

In contrast, t has an inferred size, and the number of initial values is the size of the array.

Also, the char type will not display 0 as a zero. '0' is the digit zero. 0 or '\0' -- the character -- is a null. Unless you have some specific reason, printing the values of i with printf("%d ", i[row][col]); is probably the easiest way.

Also posted here.

Thanks a lot!
This fixed my code