if Statements

if Statements

The if statement is how a program decides: if something is true, do this.

The basic form

if (condition) {
    // run this code when condition is true
}

A real example

int x = 20;
int y = 18;
if (x > y) {
    printf("x is greater than y");
}

Output: x is greater than y

The condition can be any truthy value

C treats 0 as false and anything non-zero as true:

int score = 100;
if (score) {
    printf("You have points!");
}

The braces are important

Without braces, only the very next statement belongs to the if:

if (x > y)
    printf("x is greater than y");   // only this line is inside the if

TL;DR

• if (condition) { ... } runs the block when the condition is true.
• 0 is false; any non-zero value is true.
• Braces bundle multiple statements into the if body.
• Without braces, only the next line belongs to the if.