How can I use an array of function pointers?
How should I use array of function pointers in C?
How can I initialize them?
Solution 1:
You have a good example here (Array of Function pointers), with the syntax detailed.
int sum(int a, int b);
int subtract(int a, int b);
int mul(int a, int b);
int div(int a, int b);
int (*p[4]) (int x, int y);
int main(void)
{
int result;
int i, j, op;
p[0] = sum; /* address of sum() */
p[1] = subtract; /* address of subtract() */
p[2] = mul; /* address of mul() */
p[3] = div; /* address of div() */
[...]
To call one of those function pointers:
result = (*p[op]) (i, j); // op being the index of one of the four functions
Solution 2:
The above answers may help you but you may also want to know how to use array of function pointers.
void fun1()
{
}
void fun2()
{
}
void fun3()
{
}
void (*func_ptr[3])() = {fun1, fun2, fun3};
main()
{
int option;
printf("\nEnter function number you want");
printf("\nYou should not enter other than 0 , 1, 2"); /* because we have only 3 functions */
scanf("%d",&option);
if((option>=0)&&(option<=2))
{
(*func_ptr[option])();
}
return 0;
}
You can only assign the addresses of functions with the same return type and same argument types and no of arguments to a single function pointer array.
You can also pass arguments like below if all the above functions are having the same number of arguments of same type.
(*func_ptr[option])(argu1);
Note: here in the array the numbering of the function pointers will be starting from 0 same as in general arrays. So in above example fun1
can be called if option=0, fun2
can be called if option=1 and fun3
can be called if option=2.