Driver code
int main ( ) { pair < int , int > a [ ] = { { 1 , 3 } , { 4 , 7 } , { 8 , 11 } } ; int n = sizeof ( a ) / sizeof ( a [ 0 ] ) ; int k = 6 ; int index = findNumber ( a , n , k ) ; if ( index != -1 ) cout << index ; else cout << -1 ; return 0 ; }