Question

#include <string>
    #include <iostream>
    using namespace std;
    int main(){
        string s1="123"; //Set up string 1
        string s2="356"; //Set up string 2
        string s3;       //Setup string 3

this code should print the result 12356.

Answer 1

Your “loop through s3” code is empty. You should do some checking inside your loop. You should also set is_c_in_s3 to false before the loop, and check for it to be false after the loop.

bool is_c_in_s3=false;
for(int j=0;j<s3.size();j++){    //Loop though s3
    if (c == s3[j]) {
        is_c_in_s3=true;
        break;
    }
}
if (!is_c_in_s3) {
    s3+=c; //Add the element to String 3
}