Data Type Visual C++ .NET

#include "stdafx.h"
#using 
using namespace System;
int main(void) {
    int a = 5; 
    double b = 5.4;
    Console::WriteLine(a.ToString("c"));
    Console::WriteLine(a.ToString("d"));
    Console::WriteLine(a.ToString("e"));
    Console::WriteLine(a.ToString("f"));
    Console::WriteLine(b.ToString("c"));
    Console::WriteLine(b.ToString("e"));
    return 0;
}