Function Pointer Implementation

Example of call function by Function Pointer

Hi friends in this blog i will discuss about function call by function pointer by take example of performing simple arithmetic operation (Addition, Subtraction, Multiplication and Division) o two numbers. We will discuss this example by dividing function in four simple 5 steps:

• Function Declaration
• Function Definition
• Function Pointer Declaration
• Assigning Function address to Function Pointers
• Call Function by Function Pointer

Function Declaration

When we declare any function we tell the compiler about function name, function return type and passing parameters to function. Following lines declare the function for ADD, SUB, MUL and DIV.

/*********function Declaration**********/

int ADD_2_Number(int x, int y);

int SUB_2_Number(int x, int y);

int MUL_2_Number(int x, int y);

int DIV_2_Number(int x, int y);

Function Definition

Function definition explains the working of function. In Function definition we implement the actual working of function. 

/*********Function Definition***********/

int ADD_2_Number(int x, int y)

{

    return (x+y);

}

int SUB_2_Number(int x, int y)

{

    return(x-y);

}

int MUL_2_Number(int x, int y)

{

    return(x*y);

}

int DIV_2_Number(int x, int y)

{

    return(x/y);

}

Function Pointer Declaration

int (*Funptr1)(int, int);         //Function pointer Declaration

int (*Funptr2)(int, int);         //Function pointer Declaration 

int (*Funptr3)(int, int);         //Function pointer Declaration

int (*Funptr4)(int, int);         //Function pointer Declaration

in above lines we have declare four function pointers Funptr1, Funptr2, Funptr3, Funptr4 with return types and parameters according to parameter list passing to function ADD_2_Number, SUB_2_Number, MUL_2_Number, DIV_2_Number.

Assigning Function address to Function Pointers

­ Funptr1 = &ADD_2_Number;    //assign ADD_2_Number address to Funptr1

Funptr2 = &SUB_2_Number;    //assign ADD_2_Number address to Funptr2

Funptr3 = &MUL_2_Number;    //assign ADD_2_Number address to Funptr3

Funptr4 = &DIV_2_Number;    //assign ADD_2_Number address to Funptr4

Call Function by Function Pointer

RESULT1 = (* Funptr1)(34,67);//add function call by function pointer

In this we call the ADD_2_Numbers by function pointer Funptr1. Result of addition will be stored in RESULT1 variable. Where RESULT1 is an integer type variable. Similarly we can call all other function using function pointer. 

RESULT2 =(* Funptr2)(89,12);//sub function call by function pointer 

RESULT3 =(* Funptr3)(89,2);//mul function call by function pointer 

RESULT4 =(* Funptr4)(525,5);//div function call by function pointer 

Thanks for reading this Blog!!!!!!