Initializing c++ string with integer and chars

#include <iostream>
#include <string>
using namespace std;

int main() {
    string str {5, 'c'};
    cout << str;  // "\005c"
}

Output: c

With gdb, it confirms that str contains "\005c" with str[0] = '\005' str[1] = 'c'

Why str[0] is not being printed in output console? Used c++ version: c++11