ifswitchtest.java

递归子程序法：对应每个非终结符语法单元编一个独立的处理过程（或子程序）。语法分析从读入第一个单词开始

	/** 
	 * Java语言实验参考程序
	 * Company 北京师范大学计算机系
 
	 * @author 孙一林
	 * @version 1.0
	 */

import java.io.*;
public class IfSwitchTest {
  public static void main(String[] args) throws IOException {
    char c_Ch;
    System.out.println("Input a Number:");
    c_Ch = (char)System.in.read();
    if(( 0x39 >= c_Ch ) && (c_Ch >= 0x30)){   // 判断0~9键
      System.out.println("The Number is 0~9 Key ");
      switch(c_Ch){                           // 0~9分支
        case '0':System.out.println("The Number is 0 Key ");
        break;
        case '1':System.out.println("The Number is 1 Key ");
        break;
        case '2':System.out.println("The Number is 2 Key ");
        break;
        case '3':System.out.println("The Number is 3 Key ");
        break;
        case '4':System.out.println("The Number is 4 Key ");
        break;
        case '5':System.out.println("The Number is 5 Key ");
        break;
        case '6':System.out.println("The Number is 6 Key ");
        break;
        case '7':System.out.println("The Number is 7 Key ");
        break;
        case '8':System.out.println("The Number is 8 Key ");
        break;
        case '9':System.out.println("The Number is 9 Key ");
        break;
      }
    }
    else{
      System.out.println("The Number is an Other Key ");
    }
  }
}