case使用例子
- #include <iostream>
- using namespace std;
- int main()
- {
- char choice;
- cout << "Enter A, B, or C: ";
- cin >> choice;
- switch (choice)
- {
- case ‘A‘ :
- cout<< "You entered A. \n";
- case ‘B‘ :
- cout << "You entered B. \n";
- case ‘C‘ :
- cout << "You entered C.\n";
- default:
- cout << "You did not enter A, B, or C!\n";
- }
- return 0;
- }
程序运行结果:
Enter A, B, or C: A
You entered A.
You entered B.
You entered C.
You did not enter A, B, or C!
在没有 break 语句之后,此程序“渎职”放行了匹配 case 表达式下面的所有语句,使它们都被执行了,但有时这样的效果也正是程序员想要的,如下面所示:
- #include <iostream>
- using namespace std;
- int main()
- {
- char feedGrade;
- //Get the desired grade of feed
- cout << "Our dog food is availablein three grades:\n";
- cout << "A, B, and C. Which do you want pricing for? ";
- cin >> feedGrade;
- // Find and display the price
- switch(feedGrade)
- {
- case ‘a‘:
- case ‘A‘:
- cout << "30 cents per pound.\n";
- break;
- case ‘b‘:
- case ‘B‘:
- cout << "30 cents per pound.\n";
- break;
- case ‘c‘:
- case ‘C‘:
- cout << "15 cents per pound.\n";
- break;
- default :
- cout << "That is an invalid choice.\n";
- }
- return 0;
- }
程序输出结果:
Our dog food is available in three grades:
A, B, and C. Which do you want pricing for? b
20 cents per pound.
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