Why I don't need brackets for loop and if statement

Question

I don't understand why I don't need brackets in this case

for (int i = 0; i < 10; i++) 
    if (num[i] < min) 
        min = num[i];

And why I need brackets in this case

int num[10], min;
for (int i = 0; i < 10; i++) {
        cout << "enter 10 numbers" << endl;
        cin >> num[i];
}

Answer 1

Both the for and the if have to be followed by a "statement". A "statement" can be a simple statement, like min = num[i];, a more complicated one like if (num[i] < min) min = num[i]; or it can be a compound statement (i.e., zero or more simple statements enclosed in curly braces), like { std::cout << "enter 10 numbers\n"; std::cin >> num[i]; }

Some people think that cluttering simple statements with syntactically redundant curly braces is good style. Others don't.

Answer 2

Because you don't.

They are optional. That is just how it is.

If you don't use braces to group multiple statements into one, then only the first statement following the for or if preamble is considered part of that construct. (But this rule is transitive, so your assignment is part of your if is part of your for!)

It is important to note that indentation has no effect.

Many people believe^{[citation needed]} that you should always use braces, for clarity.