Usage of switch statement in c++

The switch statement in C is a selection construct used to execute different blocks of code based on the value of a variable or expression, converting multiple if-else statements into more concise code. Its usage includes: specifying an expression to evaluate. Add multiple case statements for the constant or literal values ​​to be matched. Each case statement must be followed by a break statement. Optionally add a default statement to be executed if there is no matching case.

Usage of switch statement in C

The switch statement is a selection structure that is based on a variable or expression The value executes different blocks of code. It's an efficient way to convert multiple if-else statements into cleaner and shorter code.

Grammar:

switch (expression) {
    case value1:
        // 代码块 1
        break;
    case value2:
        // 代码块 2
        break;
    ...
    default:
        // 如果没有匹配的 case，执行此代码块
}

Usage details:

• expression: To be evaluated variable or expression.
• value1, value2, ...: represents the constant or literal value to be matched.
• case: is used to specify the code block to be executed. Each case must contain a break statement to exit the switch statement.
• default: Optional, a code block that is executed when there is no matching case.

Note:

• expression must be an integer or enumeration type.
• value1, value2, etc. must be compatible with the type of expression.
• The order of case statements does not matter, but is usually organized by value size.
• You can omit the break statement through the fallthrough keyword to execute multiple consecutive code blocks.

Example:

The following example demonstrates how to use the switch statement in C:

int day = 3;

switch (day) {
    case 1:
        cout << "星期一" << endl;
        break;
    case 2:
        cout << "星期二" << endl;
        break;
    case 3:
        cout << "星期三" << endl;
        break;
    case 4:
        cout << "星期四" << endl;
        break;
    case 5:
        cout << "星期五" << endl;
        break;
    default:
        cout << "无效的日期" << endl;
}

In this case, when day A value of 3 causes the switch statement to execute the "Wednesday" block of code.

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