iostream
이라는 헤더파일을 사용한다.#include <iostream>
int main()
{
int x = 1024;
double pi = 3.141592;
std::cout << "I love this lecture!\n" << std::endl;
std::cout << "x is " << x << " pi is " << pi << std::endl;
using namespace std;
cout << "abc" << "\t" << "def" << endl;
cout << "ab" << "\t" << "cdef\n" << endl;
// Input Exercising
int origin = 1;
cout << "Before you input, origin was " << origin << endl;
cout << "input any number : ";
cin >> origin;
cout << "origin has changed to " << origin << endl;
return 0;
}
출력결과
I love this lecture!x is 1024 pi is 3.14159
abc def
ab cdefBefore you input, origin was 1
input any number : 5
origin has changed to 5
#include <iostream>
using namespace std;
int add(int a, int b); // forward declaration
int multiply(int a, int b);
int subtract(int a, int b);
int main() {
cout << add(1, 2) << endl;
cout << subtract(1, 2) << endl;
return 0;
}
// definition
int add(int a, int b)
{
return a + b;
}
int multiply(int a, int b)
{
return a * b;
}
int subtract(int a, int b)
{
return a - b;
}
경로
" 로 호출한다.#include <iostream>
#include "add.h"
//#include "MyHeaders/add.h"
using namespace std;
int main()
{
cout << add(1, 2) << endl;
return 0;
}
#pragma once
int add(int x, int y);
int add(int x, int y)
{
return x + y;
}
실행결과
3
->이를 방지하기 위해 헤더가드가 필요하다.
#include <iostream>
#include "my_work.h"
#include "add.h"
using namespace std;
int main()
{
doSomething();
return 0;
}
#pragma once
#include "add.h"
void doSomething()
{
add(1, 2);
}
#pragma once
int add(int a, int b)
{
return a + b;
}
#include <iostream>
namespace MySpace1
{
namespace InnerSpace
{
int my_funtion()
{
return 0;
}
}
int doSomething(int a, int b)
{
return a + b;
}
}
namespace MySpace2
{
int doSomething(int a, int b)
{
return a * b;
}
}
using namespace std;
int main()
{
using namespace MySpace1;
doSomething(1, 2);
using namespace MySpace1::InnerSpace;
my_funtion();
//cout << MySpace1::doSomething(3, 4) << endl;
//cout << doSomething(3, 4) << endl;
return 0;
}
- 실행되는 doSomething()은 MySpace1의 doSomeThing이다.
- MySpace1::InnerSpace 도 한번에 생략 가능하다.