Dynamic 2D Array(Matrix) Crashes When Rows are Bigger Than Column In C-CodePudding

I was Trying to make 2D Array for Dynamic Allocation of a Matrix in but it crashes When the size of Rows are Bigger Than size of columns. Please Help. Btw I use DevC as A IDE.

//To create a Matrix with user defined value enter its value and display its content
#include<stdio.h>
#include<stdlib.h>
void display(int**,int,int);
int main()
{
    int **a,r,c,i,j;
    printf("Enter Size of Row of Matrix\n");
    scanf("%d",&r);
    printf("Enter Size of Column of matrix\n");
    scanf("%d",&c);
    a=(int**)calloc(r,sizeof(int*));
    for(i=0;i<c;i  )
    {
        a[i]=(int*)calloc(c,sizeof(int));
    }
    printf("Enter Elements of Matrix\n");
    for(i=0;i<r;i  )
    {
        for(j=0;j<c;j  )
        {
            printf("Enter Element(%d,%d)\n",i 1,j 1);
            scanf("%d",&a[i][j]);
        }
    }
    printf("The Matrix\n");
    display(a,r,c);
    return 0;
}
void display(int **arr,int r,int c)
{
    int i,j;
    for(i=0;i<r;i  )
    {
        for(j=0;j<c;j  )
        {
            printf("%d\t",arr[i][j]);
        }
        printf("\n");
    }
}

CodePudding user response：

Here:

a=(int**)calloc(r,sizeof(int*));
for(i=0;i<c;i  )
{
    a[i]=(int*)calloc(c,sizeof(int));
}

You declare an array of r elements, but you initialize c of them. Later you try to write into uninitialized memory, which is Undefined Behavior. Change the loop:

a=(int**)calloc(r,sizeof(int*));
for(i=0;i<r;i  )
{
    a[i]=(int*)calloc(c,sizeof(int));
}