Passing Pointers to Functions to Other Functions - C++ Function

C++ examples for Function:Function Pointer

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Description

Passing Pointers to Functions to Other Functions

Demo Code

#include <iostream> 
 
void square(int&,int&); 
void cube(int&, int&); 
void swap(int&, int&); 
void getVals(int&, int&); 
void printVals(void (*)(int&, int&),int&, int&); 
 
int main() /*from w ww.  j  a v  a 2s  .c o  m*/
{ 
    int valOne=1, valTwo=2; 
    int choice; 
    bool fQuit = false; 
 
    void (*pFunc)(int&, int&); 
 
    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 == true) 
                 break; 
            printVals(pFunc, valOne, valTwo); 
    } 
 
    return 0; 
} 
 
void printVals(void (*pFunc)(int&, int&),int& x, int& y) 
{ 
    std::cout << "x: " << x << " y: " << y << "\n"; 
    pFunc(x, 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


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