Driver code
int main ( ) { int n = 55 ; if ( isTriangular ( n ) ) cout << " The ▁ number ▁ is ▁ a ▁ triangular ▁ number " ; else cout << " The ▁ number ▁ is ▁ NOT ▁ a ▁ triangular ▁ number " ; return 0 ; }