구차니의 잡동사니 모음

#include <stdio.h>

void testout1(const char *s) {
  printf("시험출력1:%s\n", s);
}

void testout2(const char *s) {
  printf("시험출력2:%s\n", s);
}

// 함수포인터 변수
void (*funcPtr)(const char *s);

int main() {
  // 함수포인터를 testout1, testout2로 각각 대입해보고 실행해본다.
  funcPtr = testout1;
  funcPtr("테스트");
  funcPtr = testout2;
  funcPtr("테스트");
}

// more than one returning value
#include <iostream>
using namespace std;

void prevnext (int x, int& prev, int& next)
{
  prev = x-1;
  next = x+1;
}

int main ()
{
  int x=100, y, z;
  prevnext (x, y, z);
  cout << "Previous=" << y << ", Next=" << z;
  return 0;
}

C++ references differ from pointers in several essential ways:

• It is not possible to refer directly to a reference object after it is defined; any occurrence of its name refers directly to the object it references.
• Once a reference is created, it cannot be later made to reference another object; it cannot be reseated. This is often done with pointers.
• References cannot be null, whereas pointers can; every reference refers to some object, although it may or may not be valid.
• References cannot be uninitialized. Because it is impossible to reinitialize a reference, they must be initialized as soon as they are created. In particular, local and global variables must be initialized where they are defined, and references which are data members of class instances must be initialized in the initializer list of the class's constructor. For example: