Question

E5.6Write a function

string middle(string str)

that returns a string containing the middle character in str if the length of str is odd, or the two middle characters if the length is even. For example, middle("middle") returns "dd".

Please explain in detail. Use conditions if possible.

Answer 1

#include <iostream>
#include <string>

using namespace std;

string middle(string s) {
    if (s.size() % 2 == 0) {    // if string is of even length
        return s.substr((s.size()-1)/2, 2); // return middle 2 characters
    } else {    // if string is of even odd length
        return s.substr(s.size()/2, 1); // then return the middle single character
    }
}

int main() {
    cout << middle("middle") << endl;
    cout << middle("abcde") << endl;
    return 0;
}