I can't double characters inside string with function

Question

I am trying to create a simple function that double the characters inside of a string and outputs the new string. Ex. "hello world" would become "hheelloo wwoorrl

Answer 1

using namespace std;
string doubleChar(string str) {
    string newString(str.size() * 2, '\0');
    for(int i =0;i

The length of result should be set twice of the input. And index should be multiplied by 2.