Embedded Systems Hints,Faqs and Useful Info: Pointer to functions Explained

Thursday, July 21, 2011

Pointer to functions Explained

A good explanation of Pointer to functions

#include 



int sum(int x, int y)

{

   return x + y;

}



int product(int x, int y)

{

   return x * y;

}





int main()

{

   int a = 13;

   int b = 5;

   int result = 0;

   int (*pfun)(int, int);



   pfun = sum;

   result = pfun(a, b);

   printf("\npfun = sum   result = %d", result);



   pfun = product;

   result = pfun(a, b);

   printf("\npfun = product         result = %d", result);



}



Source: http://www.java2s.com/Code/C/Function/Pointingtofunctions.htm

1 comment:

SivaKumar.P said...: More On this

Initialize the function pointer array

#include

int sum(int a, int b);
int subtract(int a, int b);
int mul(int a, int b);
int div(int a, int b);

/* initialize the pointer array */
int (*p[4]) (int x, int y) = {
sum, subtract, mul, div
} ;

int main(void)
{
int result;
int i = 2, j = 2, op;

printf("0: Add, 1: Subtract, 2: Multiply, 3: Divide\n");
do {
printf("Enter number of operation: ");
scanf("%d", &op);
} while(op<0 || op>3);

result = (*p[op]) (i, j);
printf("%d", result);

return 0;
}

int sum(int a, int b)
{
return a + b;
}

int subtract(int a, int b)
{
return a - b;
}

int mul(int a, int b)
{
return a * b;
}

int div(int a, int b)
{
if(b)
return a / b;
else
return 0;
}

Source: http://www.java2s.com/Code/C/Function/Initializethefunctionpointerarray.htm; July 21, 2011 at 2:34 PM