# C++ Program to Find Sum of Matrix Diagonal

Write a C++ Program to Find the Sum of Matrix Diagonal with an example. In this C++ example, we used for loop to iterate matrix rows and adding items of the diagonal items (sum = sum + sumDgnalArr[rows][rows]).

```#include<iostream>
using namespace std;

int main()
{
int i, j, rows, columns, sum = 0;

cout << "\nPlease Enter the rows and Columns =  ";
cin >> i >> j;

int sumDgnalArr[i][j];

cout << "\nPlease Enter the Items\n";
for(rows = 0; rows < i; rows++)	{
for(columns = 0; columns < i; columns++) {
cin >> sumDgnalArr[rows][columns];
}
}

for(rows = 0; rows < i; rows++)
{
sum = sum + sumDgnalArr[rows][rows];
}

cout << "\nThe Sum of Diagonal Elements = " << sum;

return 0;
}```
``````Please Enter the rows and Columns =  3 3

Please Enter the Items
10 20 30
40 50 60
70 80 90

The Sum of Diagonal Elements = 150``````

In this C++ program to calculate the sum of the Matrix Diagonal, we used extra cout statements to show you the iteration number, row, column value, and the total at each iteration.

```#include<iostream>
using namespace std;

int main()
{
int i, j, rows, columns, sum = 0;

cout << "\nPlease Enter Matrix rows and Columns to find Diagonal Sum =  ";
cin >> i >> j;

int sumDgnalArr[i][j];

cout << "\nPlease Enter the Matrix Items\n";
for(rows = 0; rows < i; rows++)	{
for(columns = 0; columns < i; columns++) {
cin >> sumDgnalArr[rows][columns];
}
}

for(rows = 0; rows < i; rows++)
{
cout << "\nIteration = " << rows + 1 << ", Row Number = " << rows << " and Sum = " << sum;
sum = sum + sumDgnalArr[rows][rows];
cout <<  "\nsumDgnalArr["<<rows<<"]["<< rows <<"] = " << sumDgnalArr[rows][rows] <<
" and sum + sumDgnalArr["<<rows<<"]["<<rows <<"] = " << sum << endl;
}

cout << "\nThe Sum of Diagonal Elements in this Matrix = " << sum;

return 0;
}```

## C++ Program to Find Sum of Matrix Diagonal using a While Loop

```#include<iostream>
using namespace std;

int main()
{
int i, j, rows, columns, sum = 0;

cout << "\nPlease Enter rows and Columns =  ";
cin >> i >> j;

int sumDgnalArr[i][j];

cout << "\nPlease Enter the Items\n";
for(rows = 0; rows < i; rows++)	{
for(columns = 0; columns < i; columns++) {
cin >> sumDgnalArr[rows][columns];
}
}

rows = 0;
while(rows < i)
{
sum = sum + sumDgnalArr[rows][rows];
rows++;
}

cout << "\nThe Sum of Diagonal Elements = " << sum;

return 0;
}```
``````Please Enter rows and Columns =  3 3

Please Enter the Items
10 22 33
44 55 66
77 88 99

The Sum of Diagonal Elements = 164``````