C++ Program to find Matrix is an Identity Matrix

Write a C++ Program to find Matrix is an Identity Matrix with an example. A C++ Identity Matrix is a square matrix whose main diagonal items are 1’s, and all the other elements are zeros.

In this C++ Identity Matrix example, we allow the user to enter the rows and columns. Next, we used the C++ nested for loop to iterate the Matrix. Within the for loop, we used the C++ If statement to check whether the main diagonal items are ones and the non-diagonal items are zeros. If it is true, we changed the Flag value to 0, and apply the break statement to exit from the for loop. Next, we used the C++ If Else statement to print the identity matrix output based on the Flag value.

```// C++ Program to Check for Identity Matrix using For Loop
#include<iostream>
using namespace std;

int main()
{
int i, j, rows, columns, flag = 1;

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

int identMatrix[i][j];

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

for(rows = 0; rows < i; rows++)
{
for(columns = 0; columns < j; columns++)
{
if(identMatrix[rows][columns] != 1 && identMatrix[columns][rows] != 0)
{
flag = 0;
break;
}
}
}
if(flag == 1)
{
cout << "\nThe Matrix that you entered is an Identity Matrix";
}
else
{
cout << "\nThe Matrix that you entered is Not an Identity Matrix";
}

return 0;
}```

This  C++ code for identity matrix uses the Else If Statement to check whether the given matrix is an identity matrix.

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

int main()
{
int i, j, rows, columns, flag = 1;

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

int identMatrix[i][j];

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

for(rows = 0; rows < i; rows++)
{
for(columns = 0; columns < j; columns++)
{
if(rows == columns && identMatrix[rows][columns] != 1)
{
flag = 0;
}
else if(rows != columns && identMatrix[rows][columns] != 0)
{
flag = 0;
}
}
}
if(flag == 1)
{
cout << "\nThe Matrix that you entered is an Identity Matrix";
}
else
{
cout << "\nThe Matrix that you entered is Not an Identity Matrix";
}

return 0;
}```
``````Please Enter Matrix rows and Columns to find Identity Matrix =  3 3

Please Enter the Identity Matrix Items
1 0 0
0 1 0
0 0 1

The Matrix that you entered is an Identity Matrix``````

Let me try non identity matrix.

``````Please Enter Matrix rows and Columns to find Identity Matrix =  3 3

Please Enter the Identity Matrix Items
1 0 0
0 0 1
0 1 0

The Matrix that you entered is Not an Identity Matrix``````

C++ Program to find Matrix is an Identity Matrix using a While Loop

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

int main()
{
int i, j, rows, columns, flag = 1;

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

int identMatrix[i][j];

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

rows = 0;
while(rows < i )
{
columns = 0;
while(columns < j)
{
if(rows == columns && identMatrix[rows][columns] != 1)
{
flag = 0;
}
else if(rows != columns && identMatrix[rows][columns] != 0)
{
flag = 0;
}
columns++;
}
rows++;
}
if(flag == 1)
{
cout << "\nThe Matrix that you entered is an Identity Matrix";
}
else
{
cout << "\nThe Matrix that you entered is Not an Identity Matrix";
}

return 0;
}```
``````Please Enter Matrix rows and Columns to find Identity Matrix =  3 3

Please Enter the Identity Matrix Items
1 0 0
0 1 0
0 0 1

The Matrix that you entered is an Identity Matrix``````