A case statement is a control flow statement that allows a specific block of code to be executed based on the value of a variable or expression. Syntax: switch (expression) { case value1: ... break; case value2: ... break; ... default: ... }. Usage scenarios: Handle a limited number of known situations, such as selecting menu items based on user input, handling different error codes, and performing specific operations based on data types.
The use of case statements in Java
What is a case statement?
A case statement is a control flow statement that allows a specific block of code to be executed based on the value of a variable or expression.
The syntax of case statement
switch (expression) { case value1: // 代码块 1 break; case value2: // 代码块 2 break; ... default: // 默认情况下执行的代码块 }
How the case statement works
- expression is the variable or expression to be evaluated.
- value1, value2, etc. are constants or literal values representing different situations.
- If the value of expression matches any case value, the code in the case block is executed.
- If no case value matches, the code in the default block is executed.
- The break statement is used to exit a switch statement, which forces execution to continue with the rest of the program.
Usage scenarios
case statements are typically used to handle a limited number of known situations. For example:
- Select menu items based on user input
- Handle different error codes
- Perform specific operations based on data type
Note
- case value must be a constant or literal value.
- The default block is optional but is generally used to handle all other cases.
- The case statement is not necessarily written inside the switch block. They can also be nested within other switch statements.
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