Merging two similar c functions into one

Question

I have two functions that look like the ones down below and I am trying to merge the two with a function called function3 however I don't want it to check the parameter 'function' everytime it enters the while loop as it is a very poor way to do it. I am wondering if I can merge the two with only one if statement.

void function1(){
    int value,a,b;
    while(condition){
        value=a*b;
    }

}

void function2(){
    int value,a,b;
    while(condition){

        value=a+b;
    }
}


//merge two functions 
void function3(int function){
    int value,a,b
    while(condition){
        if(function==1){
            value=a*b;
        }
        else{
            value=a+b;
        }


    }
}

Answer 1

It is not clear from the code you posted what you intent to do, since you don't actually do anything with the values you calculated.

Aside, I think that you are looking for an array of functions or an array of pointers to functions.

You can use the variable function to access the function that you need, assuming it matches the array index of that function.

int function1(int a, int b) {
    return a * b;
}

int function2(int a, int b) {
    return a + b;
}

int (*f[])(int, int) = { function1, function2 };

void call_function(int function, int a, int b) {
    // check that "function" is within bounds of the array

    if (function < 0 || function >= sizeof(f) / sizeof(f[0])) {
        // handle out of bounds
    }

       // call appropriate function
    int ret_val = f[function](a, b);

    return;
}