# C++ Program to Print Lower Triangle of a Matrix

Write a C++ Program to Print Lower Triangle of a Matrix with an example. The following image shows you the lower triangle of a matrix.

In this C++ matrix lower triangle example, we used nested for loops to iterate lowerTriMatrix matrix rows and columns. Within that loop, we used C++ If Else statement (if(rows >= columns)) to check whether the row value is greater than or equal to the column value. If True, print the matrix item at that position; otherwise, print 0 in that position.

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

int main()
{
int i, j, rows, columns;

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

int lowerTriMatrix[i][j];

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

cout << "\nThe Result of the Lower Triangle Matrix is :\n";
for(rows = 0; rows < i; rows++)
{
cout << "\n";
for(columns = 0; columns < j; columns++)
{
if(rows >= columns)
{
cout << lowerTriMatrix[rows][columns] << " ";
}
else
{
cout << "0 ";
}
}
}

return 0;
}```

In this C++ Matrix Lower Triangle example, we used some extra cout statements to show you the iteration-wise row, column values, and lowerTriMatrix[rows][columns] value.

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

int main()
{
int i, j, rows, columns;

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

int lowerTriMatrix[i][j];

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

cout << "\nThe Result of the Lower Triangle Matrix is :\n";
for(rows = 0; rows < i; rows++)
{
cout << "\n";
cout << "\nRow Iteration = " << rows + 1 << ", Row Number = " << rows;
for(columns = 0; columns < j; columns++)
{
cout << "\nColumn Iteration = " << columns + 1 << ", Column Number = " <<
columns << ", and Row Number = " << rows;
cout << "\nThe result of (rows >= columns) = " << (rows >= columns) <<
" and lowerTriMatrix[" << rows << "][" << columns << "] = " << lowerTriMatrix[rows][columns] << endl;
if(rows >= columns)
{
cout << lowerTriMatrix[rows][columns] << " ";
}
else
{
cout << "0 ";
}
}
}

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

Please Enter the Matrix Items
1 2 3
4 5 6
7 8 9

The Result of the Lower Triangle Matrix is :

Row Iteration = 1, Row Number = 0
Column Iteration = 1, Column Number = 0, and Row Number = 0
The result of (rows >= columns) = 1 and lowerTriMatrix[0][0] = 1
1
Column Iteration = 2, Column Number = 1, and Row Number = 0
The result of (rows >= columns) = 0 and lowerTriMatrix[0][1] = 2
0
Column Iteration = 3, Column Number = 2, and Row Number = 0
The result of (rows >= columns) = 0 and lowerTriMatrix[0][2] = 3
0

Row Iteration = 2, Row Number = 1
Column Iteration = 1, Column Number = 0, and Row Number = 1
The result of (rows >= columns) = 1 and lowerTriMatrix[1][0] = 4
4
Column Iteration = 2, Column Number = 1, and Row Number = 1
The result of (rows >= columns) = 1 and lowerTriMatrix[1][1] = 5
5
Column Iteration = 3, Column Number = 2, and Row Number = 1
The result of (rows >= columns) = 0 and lowerTriMatrix[1][2] = 6
0

Row Iteration = 3, Row Number = 2
Column Iteration = 1, Column Number = 0, and Row Number = 2
The result of (rows >= columns) = 1 and lowerTriMatrix[2][0] = 7
7
Column Iteration = 2, Column Number = 1, and Row Number = 2
The result of (rows >= columns) = 1 and lowerTriMatrix[2][1] = 8
8
Column Iteration = 3, Column Number = 2, and Row Number = 2
The result of (rows >= columns) = 1 and lowerTriMatrix[2][2] = 9
9``````

## C++ Program to Print Lower Triangle of a Matrix using a While Loop

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

int main()
{
int size, i, j, rows, columns;

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

int lowerTriMatrix[i][j];

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

cout << "\nThe Result of the Lower Triangle Matrix is :\n";
rows = 0;
while(rows < i)
{
cout << "\n";
columns = 0;
while(columns < j)
{
if(rows >= columns)
{
cout << lowerTriMatrix[rows][columns] << " ";
}
else
{
cout << "0 ";
}
columns++;
}
rows++;
}

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

Please Enter the Matrix Items
1 2 3
9 8 7
4 7 6

The Result of the Lower Triangle Matrix is :

1 0 0
9 8 0
4 7 6 ``````