Conditional (If-Else) Statements

The conditional statement in Apex works similarly to Java.

if ([Boolean_condition]) 
    // Statement 1
else
    // Statement 2

The else portion is always optional, and always groups with the closest if. For example:

Integer x, sign;
// Your code
if (x <= 0) if (x == 0) sign = 0; else sign = -1;

is equivalent to:

Integer x, sign;
// Your code
if (x <= 0) {
    if (x == 0) {
           sign = 0; 
    } else  {
           sign = -1;
    }
}

Repeated else if statements are also allowed. For example:

if (place == 1) {
    medal_color = 'gold';
} else if (place == 2) {
    medal_color = 'silver';
} else if (place == 3) {
    medal_color = 'bronze';
} else {
    medal_color = null;
}