C program to print the sum of diagonal elements in a matrix

write a c program to print the sum of diagonal elements in a matrix.

#include<stdio .h="">

#include<conio .h="">

void main()

{

 int a[20][20],i,j,m,n,sum=0;

 clrscr();

 printf("Enter the total number of rows in array:");

 scanf("%d",&amp;m);

 printf("Enter the total number of column in array:");

 scanf("%d",&amp;n);

  for(i=0;i</conio></stdio>