Question

What is difference between these two examples:

if(firstchek)
{
    if(second)
    {
     return here();
    }
    else
    {
    return here();
    }
}

and this:

if(firstcheck)
{
    if(second)
    {
     return here();
    }
      return here();
    // else code without else
}
// code without else
// else code is here 
     return here();

Answer 1

This code:

if (someCondition)
{
    foo();
    return;
}
bar();
return;

is the same as this:

if (someCondition)
{
    foo();
}
else
{
    bar();
}
return;

The only difference is in readability. Sometimes one way is more readable, sometimes the other. See Refactoring: Replace Nested Conditional with Guard Clauses.

Nested conditionals:

double getPayAmount() {
    double result;
    if (_isDead) result = deadAmount();
    else {
        if (_isSeparated) result = separatedAmount();
        else {
            if (_isRetired) result = retiredAmount();
            else result = normalPayAmount();
        };
    }
    return result;
};

Guard clauses:

double getPayAmount() {
    if (_isDead) return deadAmount();
    if (_isSeparated) return separatedAmount();
    if (_isRetired) return retiredAmount();
    return normalPayAmount();
};