Add a Character Between Strings in C++

So basically I'm trying to add a character in the middle of a string. Normally in something like Python, this would be pretty straightforward, but I'm really not sure how to achieve this in C++. What I'm trying to achieve is something like this:

void converter(){
    converted = ":regional_indicator_" + character + ":";

}

So basically, I'm trying to add the variable character of a type char in a string. Should I be storing character as a string instead?

For reference here's all of my code:

#include <iostream>

using namespace std;

string inputLine;
char character;
string converted;

void input(){
    cout << "Please input the text in which you would like to be converted" << endl;
    cin >> inputLine;
}


void converter(){
    converted = ":regional_indicator_" + character + ":";

}
int main(){
    input();
    for (int i = 0; i < inputLine.length(); i++ ){
        character = tolower(inputLine[i]);
    }
    return 0;
}