menu.java

Java 程序设计源码 只提供了部分

class Menu{
	public static void main(String[] args)
		throws java.io.IOException{
			char choice;

			do{
				System.out.println("Help on");
				System.out.println("1. if");
				System.out.println("2. switch");
				System.out.println("3. while");
				System.out.println("4. dowhile");
				System.out.println("5. for\n");
				System.out.println("choose one");

				choice = (char)System.in.read();
			}while(choice < '1' || choice > '5');

			System.out.println("\n");

			switch(choice){
				case '1':
					System.out.println("The if:\n");
					System.out.println("if(condition) statement");
					System.out.println("else statement");
					break;
				case '2':
					System.out.println("The switch:\n");
					System.out.println("switch(expression) {");
					System.out.println("case constant");
					System.out.println("statement sequence;");
					System.out.println("break;");
					System.out.println("// ...");
					System.out.println("}");
					break;
				case '3':
					System.out.println("The while:\n");
					System.out.println("while(condition)");
					System.out.println("statement");
					break;
				case '4':
					System.out.println("The do-while:\n");
					System.out.println("do {");
					System.out.println("statement");
					System.out.println("}while(condition);");
					break;
				case '5':
					System.out.println("The for:\n");
					System.out.println("for(init;condition;iteration) {");
					System.out.println("statement");
					System.out.println("}");
					break;

			}
		}

}