I know what the output is (It's 17 18 19 all on separate lines) but how do I go about figuring this out from the given C program?

#include

void changeme(int number) {

number = number + 10;

}

int main(void) {

int x = 17;

changeme(x);

printf(%d , x);

changeme(x++);

printf(%d , x);

changeme(++x);

printf(%d , x);

return 0; }