Simple C++ program to calculate sum of diagonal elements of a matrix. code is same as the sum of elements of a matrix, we add only those elements of the matrix.
All we need to do is:
Create a 2D array.
Take input in the array.
Add all elements of left diagonal separately.
Add all elements of right diagonal separately.
Output the result.
C++ Program to Find Sum of Diagonals of Matrix Array
#include<iostream>
using namespace std;
int main()
{
int a[5][5],d1sum=0,d2sum=0,m,i,j;
cout<<"Enter size of the square matrix(max 5):";
cin>>m;
cout<<"\nEnter the Matrix row wise:\n";
for(i=0;i<m;i++)
for(j=0;j<m;++j)
cin>>a[i][j];
for(i=0;i<m;++i)
for(j=0;j<m;++j)
{
if(i==j)
d1sum+=a[i][j];
if(i+j==(m-1))
d2sum+=a[i][j];
}
cout<<"\nSum of 1st diagonal is "<<d1sum;
cout<<"\nSum of 2nd diagonal is "<<d2sum;
return 0;
}Output of Program
Enter size of the square matrix(max 5):6
Enter the Matrix row wise:
7
6
6′
Sum of 1st diagonal is 19720079
Sum of 2nd diagonal is -1