C++ Program to Print Upper Triangle of a Matrix

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

In this C++ matrix upper triangle example, we used nested for loops to iterate upperTriMatrix matrix rows and columns. Within that, we used C++ If Else statement (if(columns >= rows)) to check whether the column value is greater than or equal to the row value. If True, print the upperTriMatrix 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 Upper Triangle =  ";
	cin >> i >> j;
	
	int upperTriMatrix[i][j];
	
	cout << "\nPlease Enter the Matrix Items\n";
	for(rows = 0; rows < i; rows++)	{
		for(columns = 0; columns < i; columns++) {
			cin >> upperTriMatrix[rows][columns];
		}		
	}

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

 	return 0;
}

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

#include<iostream>
using namespace std;

int main()
{
	int i, j, rows, columns;
	
	cout << "\nPlease Enter Matrix rows and Columns to find Upper Triangle =  ";
	cin >> i >> j;
	
	int upperTriMatrix[i][j];
	
	cout << "\nPlease Enter the Matrix Items\n";
	for(rows = 0; rows < i; rows++)	{
		for(columns = 0; columns < i; columns++) {
			cin >> upperTriMatrix[rows][columns];
		}		
	}

 	cout << "\nThe Result of the Upper 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 (columns >= rows) = " << (columns >= rows) << 
				" and upperTriMatrix[" << rows << "][" << columns << "] = " << upperTriMatrix[rows][columns] << endl;
    		if(columns >= rows)
    		{
    			cout << upperTriMatrix[rows][columns] << " ";
			}
			else
			{
				cout << "0 ";
			}
   	 	}
  	}	

 	return 0;
}

Please Enter Matrix rows and Columns to find Upper Triangle =  2 2

Please Enter the Matrix Items
10 20
30 40

The Result of the Upper Triangle Matrix is :


Row Iteration = 1, Row Number = 0
Column Iteration = 1, Column Number = 0, and Row Number = 0
The result of (columns >= rows) = 1 and upperTriMatrix[0][0] = 10
10 
Column Iteration = 2, Column Number = 1, and Row Number = 0
The result of (columns >= rows) = 1 and upperTriMatrix[0][1] = 20
20 

Row Iteration = 2, Row Number = 1
Column Iteration = 1, Column Number = 0, and Row Number = 1
The result of (columns >= rows) = 0 and upperTriMatrix[1][0] = 30
0 
Column Iteration = 2, Column Number = 1, and Row Number = 1
The result of (columns >= rows) = 1 and upperTriMatrix[1][1] = 40
40

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

#include<iostream>
using namespace std;

int main()
{
	int i, j, rows, columns;
	
	cout << "\nPlease Enter Matrix rows and Columns to find Upper Triangle =  ";
	cin >> i >> j;
	
	int upperTriMatrix[i][j];
	
	cout << "\nPlease Enter the Matrix Items\n";
	for(rows = 0; rows < i; rows++)	{
		for(columns = 0; columns < i; columns++) {
			cin >> upperTriMatrix[rows][columns];
		}		
	}

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

 	return 0;
}

Please Enter Matrix rows and Columns to find Upper Triangle =  3 3

Please Enter the Matrix Items
11 22 33
44 55 66
77 88 99

The Result of the Upper Triangle Matrix is :

11 22 33 
0 55 66 
0 0 99