명품 c++ programming 6장 8번

#include<iostream>
#include<string>
using namespace std;
 
class Trace
{
    static string tag[100], log[100];
    static int count;
public:
    static void put(const char* t,const char* l);
    static void print(const char* t = NULL);
};
 
string Trace::tag[100], Trace::log[100];
int Trace::count = 0;
 
void Trace::put(const char* t, const char* l)
{
    tag[count] = t;
    log[count] = l;
    count++;
}
 
void Trace::print(const char* t)
{
    if (t == NULL)
    {
        cout << "---모든 Trace 정보를 출력합니다.---" << endl;
        for (int i = 0; i < count; i++)
        {
            cout << tag[i] << ":" << log[i]<<endl;
        }
    }
    else
    {
        cout << t << "---태그의 Trace 정보를 출력합니다.---"<< endl;
        for (int i = 0; i < count; i++)
        {
            if(t == tag[i])
            cout << tag[i] << ":" << log[i] << endl;
        }
    }
}
 
 
void f()
{
    int a, b, c;
    cout << "두 개의 정수를 입력하세요>>";
    cin >> a >> b;
    Trace::put("f()", "정수를 입력 받았음");
    c = a + b;
    Trace::put("f()", "합 계산");
    cout << "합은" << c << endl;
}
 
int main()
{
    Trace::put("main()", "프로그램 시작합니다.");
    f();
    Trace::put("main()", "종료");
 
    Trace::print("f()");
    Trace::print();
}