# C++ code to check triangular number

Suppose we have a number n. We have to check whether the number is triangular number or not. As we know, if n dots (or balls) can be arranged in layers to form a equilateral triangle then n is a triangular number.

So, if the input is like n = 10, then the output will be True.

## Steps

To solve this, we will follow these steps −

for initialize i := 1, when i <= n, update (increase i by 1), do:
if i * (i + 1) is same as 2 * n, then:
return true
return false

## Example

Let us see the following implementation to get better understanding −

#include <bits/stdc++.h>
using namespace std;
bool solve(int n){
for (int i = 1; i <= n; i++){
if (i * (i + 1) == 2 * n){
return true;
}
}
return false;
}
int main(){
int n = 10;
cout << solve(n) << endl;
}

## Input

10

## Output

1