Driver code
int main ( ) { string str = " geeksforgeeks " ; cout << " The ▁ input ▁ string ▁ is ▁ " << str << endl ; int len = longestUniqueSubsttr ( str ) ; cout << " The ▁ length ▁ of ▁ the ▁ longest ▁ non - repeating ▁ " " character ▁ substring ▁ is ▁ " << len ; return 0 ; }