MATRIX: PROGRAM TO CHECK WHETHER THE MATRIX IS IDENTITY OR NOT

#include<stdio.h>
void main()
{
int mat[3][3],i,j,f=1;
printf("Enter the matrix:");
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
scanf("%d",&mat[i][j]);
}
}
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
if(mat[i][j]!=1&&mat[j][i]!=0)
{
f=0;
break;
}
}
}
if(f==1)
printf("matrix is identity");
else
printf("matrix is not identity");
}