/*
	Project 4-1
	
	Convert the help system from Project 3-3 into a Help class.
*/
class Help {
	void helpon(int what) {
		switch(what) {
			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 for:\n");
				System.out.println("for(initialization; condition; iteration) statement;");
				break;
			case '4':
				System.out.println("The while:\n");
				System.out.println("while(condition) statement;");
				break;
			case '5':
				System.out.println("The do-while:\n");
				System.out.println("do {");
				System.out.println("  statement;");
				System.out.println("} while (condition);");
				break;
			case '6':
				System.out.println("The break:\n");
				System.out.println("break; or break label;");
				break;
			case '7':
				System.out.println("The continue:\n");
				System.out.println("continue; or continue label;");
				break;
		}
		System.out.println();
	}
	
	void showmenu() {
		System.out.println("Help on:");
		System.out.println("  1. if");
		System.out.println("  2. switch");
		System.out.println("  3. for");
		System.out.println("  4. while");
		System.out.println("  5. do-while");
		System.out.println("  6. break");
		System.out.println("  7. continue\n");
		System.out.print("Choose one (q to quit): ");
	}
	
	boolean isvalid(int ch) {
		if(ch < '1' | ch > '7' & ch != 'q') return false;
		else return true;
	}
}

class HelpClassDemo {
	public static void main(String args[]) throws java.io.IOException {
		char choice;
		Help hlpobj = new Help();
		
		for(;;) {
			do {
				hlpobj.showmenu();
				do {
					choice = (char) System.in.read();
				} while(choice == '\n' | choice == '\r');
			} while( !hlpobj.isvalid(choice) );
			
			if(choice == 'q') break;
			
			System.out.println("\n");
			
			hlpobj.helpon(choice);
		}
	}
}

Convert Help to a class
Convert Help to a class