text: Driver function .
code: int main ( ) { int mat [ N ] [ N ] = { { 1 , 3 , 5 , 3 } , { 0 , 4 , 6 , 2 } , { 0 , 0 , 2 , 5 } , { 0 , 0 , 0 , 6 } } ; if ( isUpperTriangularMatrix ( mat ) ) cout << " Yes " ; else cout << " No " ; return 0 ; }