return-statement with no value，in function returning'int'

If a function returns an `int` but the `return` statement has no value, the function will return an undefined value. This can lead to unexpected behavior in your program.

For example, consider the following function:

int foo() {
    return;
}

This function has a return type of `int`, but the `return` statement has no value. When this function is called, it will return an undefined value. Depending on how the function is used in your program, this could lead to a segmentation fault or other errors.

To avoid this issue, always make sure that your `return` statements have a value that matches the return type of your function. For example:

int bar() {
    return 42;
}

This function has a return type of `int`, and the `return` statement returns the value `42`. When this function is called, it will return the value `42`.