How can a function save previous argument that was passed to it?

Question

My function needs to know the value of a previous argument that was passed to it. For example if I call this function twice, it needs to know the value passed to it in the first call to take action. How can I achieve this?

Answer 1

And that would be so nice if only C had classes. 🙄

Here's how you can do it in C:

#include <stdio.h>

void f(int n) {
static int m = 0;
printf("Old: %d", m);
m = n;
printf("\nNew: %d\n\n", m);
}

int main() {
f(3);
f(5);
f(7);
return 0;
}

Answer 2

You will have to make a variable independent from the function. Declare it outside of the function and you can instantiate it inside the function. Here's some pseudocode:

class MyClass {
var myVar

static func x(b?) {
if (myVar == null && b != null) {
myVar = b * 2
} else {
print(myVar)
}
}
}

func main() {
MyClass.x(5)
MyClass.x()
}