无法理解 function 在没有返回语句但 C 语言中有 int 返回类型时如何返回特定值

Question

This recursive function 'int f(int n)' should not return anything except when 'n == 1'. If we put n = 2,3 then y = 2 . When n = 4,5 then y = 3 , when n = 6,7,8 then **y = 4 **and so on. Here, variable x is static. Below is the code:

#include <stdio.h>
int f(int n){
        static int x=1; 
        int i;
        if(n==1){
            return 1;
        }
        else {
            for(i = 1; i<=2; i++){
                x = x + f(n-1);
                printf("%d\n",x);
            }
        }
}
int main() {
    int n = 3;
    int y =f(n);
    printf("y %d",y);
    }

Kindly help me understand how the value of y is assigned or how f() is returning such values. Thank you.

I was expecting 2,3,4,5,6,7. I am able to get those values implementing some other stuff but that is not what I want to understand. I want to understand the f() is 2, when n is 2,3. How f() is returning a value without the return statement?

Answer 1

The function f doesn't return a value on all code paths. This means undefined behavior. It may return anything, or y may remain uninitialized.