Single-entry/single-exit rule [closed]

Answer 1

No, this is not a rule, and sometimes it is even difficult/impossible to achieve. The code that has one entry and one exit point is easier to understand and debug though. Compare this:

int foo()
{
    if(something)
        return 0;
    //100 lines of code
    if(something)
        return 11;
    //100 lines of code
    if(something)
        return -1;
    //100 lines of code
    return 0;
}

and this:

int foo()
{
    int errorCode = 0;
    if(something)
        errorCode = 1;
    //100 lines of code
    if(something)
        errorCode = 11;
    //100 lines of code
    if(something)
        errorCode = -1;
    //100 lines of code
    return errorCode;
}

Now we have just one exit point, and (taking into account the variable name too) it's much easier to understand what the function does. You can also place a breakpoint onto the last return and know that this is the point where function ends, and that you will definitely hit it.