#include "function.h"
#include <iostream>
#include <string>
using namespace std;

String_Calculator::String_Calculator(const string input) {
    s = input;
}

String_Calculator &String_Calculator::Add(const string input) {
    s += input;
    return *this;
}

String_Calculator &String_Calculator::Subtract(const string input) {
    int pos = s.find_first_of(input);
    if (pos != string::npos) {
        s.erase(pos, input.length());
    } else {
        s = "error";
    }
    return *this;
}

String_Calculator &String_Calculator::DividedBy(const string input) {
    int ans = 0;
    int pos = 0;
    while (1) {
        pos = s.find(input, pos);
        if (pos == string::npos) {
            break;
        }
        ans++;
        pos++;
    }
    s = std::to_string(ans);
    return *this;
}

void String_Calculator::output(void) const {
    cout << s << endl;
    return;
}