The declaration of a function pointer always includes the return type and parentheses indicating the type of the parameters, if any. - C++ Function

C++ examples for Function:Function Pointer

  1. HOME
  2. C++
  3. Function
  4. Function Pointer

Description

The declaration of a function pointer always includes the return type and parentheses indicating the type of the parameters, if any.

Demo Code

#include <iostream> 
 
void square(int&, int&); 
void cube(int&, int&); 
void swap(int&, int&); 
void getVals(int&, int&); 
void printVals(int, int); 
 
int main() //ww  w .j av  a  2 s  .  co  m
{ 
    void (*pFunc)(int&, int&); 
    bool fQuit = false; 
 
    int valOne = 1, valTwo = 2; 
    int choice; 
    while (fQuit == false) 
    { 
            std::cout << "(0) Quit (1) Change Values " 
                  << "(2) Square (3) Cube (4) Swap: "; 
            std::cin >> choice; 
            switch (choice) 
             { 
            case 1: 
                  pFunc = getVals; 
                  break; 
            case 2: 
                  pFunc = square; 
                  break; 
            case 3: 
                  pFunc = cube; 
                  break; 
            case 4: 
                  pFunc = swap; 
                  break; 
            default : 
                  fQuit = true; 
                  break; 
             } 
 
            if (fQuit) 
                  break; 
 
            printVals(valOne, valTwo); 
            pFunc(valOne, valTwo); 
            printVals(valOne, valTwo); 
    } 
     return 0; 
 } 
  
 void printVals(int x, int y) 
 { 
     std::cout << "x: " << x << " y: " << y << "\n"; 
 } 
 
void square(int &rX, int &rY) 
{ 
    rX *= rX; 
    rY *= rY; 
} 
 
void cube(int &rX, int &rY) 
{ 
    int tmp; 
 
    tmp = rX; 
    rX *= rX; 
    rX = rX * tmp; 
 
    tmp = rY; 
    rY *= rY; 
    rY = rY * tmp; 
} 
 
void swap(int &rX, int &rY) 
{ 
    int temp; 
    temp = rX; 
    rX = rY; 
    rY = temp; 
} 
 
void getVals(int &rValOne, int &rValTwo) 
{ 
    std::cout << "New value for valOne: "; 
    std::cin >> rValOne; 
    std::cout << "New value for valTwo: "; 
    std::cin >> rValTwo; 
}

Result


Related Tutorials