//Q78, Find the sum of main diagonal elements for a square matrix.
 
#include <stdio.h>
int main() {
    int n,a[10][10],i,j,sum=0;
    for(i=0;i<n;i++)
        for(j=0;j<n;j++){
            if(i==j) sum += a[i][j];
        }
}
 
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