39. Function Pointer Dispatch Table

#include <stdio.h>

int add(int a, int b) { return a + b; }
int sub(int a, int b) { return a - b; }
int mul(int a, int b) { return a * b; }
int divide(int a, int b) { return a / b; }

int execute_command(int a, int b, int cmd) {
    // Declare function pointer array
    int (*operations[4])(int, int) = { add, sub, mul, divide };

    // Call correct operation based on command
    return operations[cmd](a, b);
}

int main() {
    int a, b, cmd;
    scanf("%d %d %d", &a, &b, &cmd);

    int result = execute_command(a, b, cmd);
    printf("%d", result);

    return 0;
}

• Each function (add, sub, etc.) has signature int func(int, int)
• Function pointer array holds them: int (*ops[4])(int, int)
• ops[cmd](a, b) directly invokes the correct one
• No branching logic used — full dispatch via pointer

✅ Very useful in ISR tables, protocol command dispatch, or FSM transitions.