Understand the C language default keywords

The default keyword is used to handle unmatched cases in switch-case statements, providing a mechanism to handle unprocessed cases, which is immediately after the last case tag, enclosed in braces {}, can contain any C code, and is optional.

Understand the C language default keywords

What is the default keyword?

The default keyword is used to handle unmatched cases in the switch-case statement. When the switch expression does not match any case tags, it executes the default code block.

The role of default keyword

The default keyword provides a mechanism for handling unprocessed cases in switch-case statements. It allows us to specify the code to be executed when all other conditions are not met. Without the default keyword, an unmatched case will cause an error in the program.

Use of default keywords

The default keyword follows the last case tag of the switch statement. It represents a special case that does not match any specific value. The default code block is enclosed in braces {}.

 <code class="c">switch (x) { case 1: // 处理case 1 break; case 2: // 处理case 2 break; default: // 处理其他所有未匹配的情况break; }</code>

Things to note about default keywords

• The default code block can contain any C code.
• The default code block is optional, but is useful for handling unmatched situations.
• If there is no default code block in the switch statement and the switch expression does not match any case, the program will execute the default code block.
• The default code block can include break statements to exit the switch-case statement.
• The default code block can be shared by multiple case tags, in which case it executes the default code block if any case matches.

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