You are confusing parenthesis () with curly braces {}
Parenthesis are used to enclose values or to define how you want a calculation to be evaluated
1+23 would give the value of 7, not 9 as you might think and that is because the * operator has precedence over the + operator and theerfore the 23 is calculated first.
To make it work to give you a value of 9, you would need to enclose specific sections of the calculation in parenthesis, e.g. (1+2)*3 - This would calculate the 1+2 first (as the parenthesis have precedence over the * and +) to get 3 then 3 gets multiplied by 3 to get 9.
Parenthesis are also used to enclose parameters on functions.
Curly braces are simply there to tell the compiler where a code block starts and ends. E.g.
for (int x; x <10; x++)
{
// do something here
}