Thread: calling functions using pointers insteded of function names

  1. #1
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    Feb 2022
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    calling functions using pointers insteded of function names

    I don't understand how a function pointer is used to call any function

    I have written a program in which i have created four functons

    Code:
     #include <stdlib.h>
    
    void function1 ()
    {
       printf("\n Hello ");	
    }
    
    
    void function2 ( int x)
    {
    	x = 2; 
    	printf("\n x = %d ");	
    }
    
    
    int function3 ( int y)
    {
    	y = 2; 
    	y++;
    	return y;	
    }
    
    
    int function4 ()
    {
    	z = 2; 
    	z++;
    	return z;	
    }
    
    
    int main ()
    {
    	
    return 0;	
    }
    I want to call each functions using pointers insteded of function names but I don't understand how to do it. mainly I am having trouble in type casting

  2. #2
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    Dec 2017
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    1,376
    Code:
    #include <stdio.h>
     
    void function1()      { printf("Hello\n"); }
    void function2(int x) { printf("x = %d\n", x); }
    int  function3(int y) { return y + 1; }
    int  function4()      { return 42; }
     
    int main ()
    {
        void (*f1)()    = function1;
        void (*f2)(int) = function2;
        int  (*f3)(int) = function3;
        int  (*f4)()    = function4;
     
        f1();
        f2(f3(f4()));
     
        return 0;   
    }
    A long time ago being crazy meant something. - Charles Manson

  3. #3
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    Quote Originally Posted by john.c View Post
    Code:
    #include <stdio.h>
     
    void function1()      { printf("Hello\n"); }
    void function2(int x) { printf("x = %d\n", x); }
    int  function3(int y) { return y + 1; }
    int  function4()      { return 42; }
     
    int main ()
    {
        void (*f1)()    = function1;
        void (*f2)(int) = function2;
        int  (*f3)(int) = function3;
        int  (*f4)()    = function4;
     
        f1();
        f2(f3(f4()));
     
        return 0;   
    }
    understood, Thanks for the effort

    Code:
    #include <stdio.h>  
    void function1()      { printf("Hello\n"); }
    void function2(int x) { printf("x = %d\n", x); }
    int  function3(int y) { return y + 1; }
    int  function4()      { return 42; }
      
    int main ()
    {
    	int a, b;
        void (*f1)()    = function1;
        void (*f2)(int) = function2;
        int  (*f3)(int) = function3;
        int  (*f4)()    = function4;
      
        a = f3(2);
        printf("a = %d\n", a); 
        b = f4();
    	printf("b = %d\n", b); 
        return 0;   
    }
    a = 3
    b = 42

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