C++ Program To Print Pascal’s Triangle (2 Ways)

by Amit Rawat · Published June 1, 2019 · Updated June 17, 2019

In this program, we will learn how to print Pascal’s Triangle using the C++ programming language.

What is Pascal’s Triangle?

In mathematics, It is a triangular array of the binomial coefficients. It is named after the French mathematician Blaise Pascal.

We will discuss two ways to code it.

Without using Factorial
Using Factorial

C++ Programming Code To Print Pascal’s Triangle

Without using Factorial

Code:-

#include<iostream>

using namespace std;
 
int main(){
    int rows, coff;
    cout << "Enter the number of rows : ";
    cin >> rows;
 
    for(int i = 0; i < rows; i++){
        coff = 1;

        for(int j = 1; j < (rows - i); j++){
            cout << "   ";
        }
        
        for(int k = 0; k <= i; k++){
            cout << "      " << coff;
            coff = coff * (i - k) / (k + 1);
        }

        cout << endl << endl;
    }

    return 0;
}

Output:-

Enter the number of rows : 5
                  1

               1      1

            1      2      1

         1      3      3      1

      1      4      6      4      1

Using Factorial

We have already discussed different ways to find the factorial of a number. So, you look up there to learn more about it.

Code:-

#include<iostream>

using namespace std;

long fact(int n){
	int c;
	long res=1;
	for(c=1; c<=n; c++)
	{
		res = res*c;
	}
	return (res);
}

int main(){
    int rows, coff;

    cout << "Enter the number of rows : ";
    cin >> rows;

	for(int i = 0; i < rows; i++){
        for(int j = 1; j < (rows - i); j++){
            cout << "   ";
        }

        for(int k = 0; k <= i; k++){
            coff = fact(i)/(fact(k)*fact(i-k));
            cout << "      " << coff;
        }
		cout << endl << endl;
	}

    return 0;
}

Output:-

Enter the number of rows : 8
                           1

                        1      1

                     1      2      1

                  1      3      3      1

               1      4      6      4      1

            1      5      10      10      5      1

         1      6      15      20      15      6      1

      1      7      21      35      35      21      7      1