Basic knowledge of C language "judgment"

C judgment
1. Judging the structure requires the programmer to specify one or more conditions to evaluate or test, and the statement to execute when the condition is true (required) and the statement to be executed if the condition is false (optional).
The C language assumes that any nonzero and non-null values are true and that 0 or null is assumed to be false.
2. Judgment statement
The C language provides the following types of judgment statements. Click the link to see the details of each statement.
Statement description
An If statement consists of a Boolean expression followed by one or more statements.
The If...else statement can be followed by an optional else statement after an if statement, and the Else statement is executed when the Boolean expression is false.
Nested IF statements you can use another if or else if statement within one if or else if statement.
Switch statement A switch statement allows you to test a situation where a variable equals multiple values.
Nested switch statements You can use another switch statement within a switch statement.

Basic knowledge of C language "judgment"