对于一个局部变量,它的作用域为它所定义的地方到它所在的语句块结束为止,那么对于变量b,它所在的最小语句块为switch{}块,那么也就说在case 0后面的部分,变量b都是可见的(注意在case 0之前变量b是无法访问的)。考虑这样一种情况,当a的值为1,那么程序就跳到case 1执行,此时b虽然可以访问,但是跳过了它的初始化过程。而如果在定
在switch 语句后,控制语句跳转到匹配的 case 标签,写在 case 标签前的语句不会被执行。 示例: // statement before all cases are never executedintx =2;switch(x) { x = x +1;// 此条语句不会执行, this statement is not executedcase1: std::cout <<"x equals 1"<< std::endl;break;case2:...
Switch case statement is used when we have multiple conditions and we need to perform different action based on the condition. When we have multiple conditions and we need to execute a block of statements when a particular condition is satisfied. In such case either we can use lengthyif..else...
c++switch case语句例子 1. 概述:C++中的switch case语句是一种分支控制语句,用于根据表达式的值选择执行不同的代码块。它通常被用来替代多个if-else语句,使代码更加简洁和易读。2. 语法和基本用法:在C++中,switch case语句的基本语法如下:```cpp switch (expression) { case value1:// code block 1 break...
case"456":{ // ... break; } // ... default:{ // ... break; } } 直接匹配字符串是不行的,C++ 中 case 只可以匹配a constant expression of the same type as the type of condition after conversions and integral promotions,所以在这里我需要把字符串转换为一个字面值整数从而进行 case 匹配。
0 - This is a modal window. No compatible source was found for this media. stdgradegradecase'A':cout<<"Excellent!"<<endl;break;case'B':case'C':cout<<"Well done"<<endl;break;case'D':cout<<"You passed"<<endl;break;case'F':cout<<"Better try again"<<endl;break;default:cout<<"...
The variable is evaluated, and its value is compared to each of the case values. Ifthe value of the variable matches a case value, the code associated with that case is executed. If the value of the variable does not match any of the case values, the code in the default case is exec...
Can I have range in switch case in C++?Nov 13, 2019 at 4:01am Shervan360 (184) Hello, I have a float number and I want to use a switch case for this.To solve float problem in the switch case, I multiply the number to 10....
Thebreakanddefaultkeywords are optional, and will be described later in this chapter The example below uses the weekday number to calculate the weekday name: Example intday =4; switch(day) { case1: cout <<"Monday"; break; case2:
switch(x){case'a':return1;case'b':return2;case'c':return3;} Exceptions(例外) In rare cases if fallthrough is deemed appropriate, be explicit and use the [[fallthrough]] annotation: 在很少的情况下,如果确信下沉处理是合适的,可以使用[[fallthrougn]]记法明确标明。