﻿ C++ exercises and solutions: Pascal triangle

# C++ exercises and solutions: Pascal triangle

## C++ arrays: Pascal triangle

This is another C++ exercise about using two-dimensional array of C++. By using two-dimensional array, write C++ program to display a table that represents a Pascal triangle of any size. In Pascal triangle, the first and the second rows are set to 1. Each element of the triangle (from the third row downward) is the sum of the element directly above it and the element to the left of the element directly above it. See the example Pascal triangle(size=5) below:

 1 1 1 1 2 1 1 3 3 1 1 4 6 4 1

Solution:

#include<iostream>
#include<conio.h>
using namespace std;

void printPascalTr(int size);
int main()
{

int size;
cout<<"Enter Pascal triangle size:";
cin>>size;

printPascalTr(size);
getch();
return 0;

}

void printPascalTr(int size){
int PascalTr[size][size];
int row,col;
//assign zero to every array element
for(row=0;row<size;row++)
for(col=0;col<size;col++)  PascalTr[row][col]=0;
//first and second rows are set to 1s
PascalTr[0][0]=1;
PascalTr[1][0]=1;
PascalTr[1][1]=1;

for(row=2;row<size;row++){
PascalTr[row][0]=1;
for(col=1;col<=row;col++){
PascalTr[row][col]=PascalTr[row-1][col-1]+PascalTr[row-1][col];
}
}
//display the Pascal Triangle
for(row=0;row<size;row++){
for(col=0;col<=row;col++){
printf("%d\t",PascalTr[row][col]);
}
cout<<endl;
}

}