Can anyone explain this code behaviour in c++?

Asked May 03 '19 at 12:54

Active May 03 '19 at 13:02

Viewed 92 times

vector<int> a(10);
vector<int> b(20);

if ((a.size() - b.size()) > 1) {
    cout << "yes";
}

Can anyone explain why this code prints "yes". If I try storing a.size() - b.size() in an int variable, it is working as expected.

edited May 03 '19 at 13:02

asked May 03 '19 at 12:54

Pankaj

1

Note the return type of `std::vector::size()`. – vahancho May 03 '19 at 12:57
1

`size()` returns an unsigned value. `10 - 20` will wrap around to a very large value. See also https://stackoverflow.com/questions/16056758/c-c-unsigned-integer-overflow – Cornstalks May 03 '19 at 12:57
a.size()-b.size()>1 is similar to a.size()!=b.size() – Adrian Maire May 03 '19 at 14:49

0 Answers0