JAVA输出流与输入流代码实例

 public class C {
   public static void main(String[] args) {
     System.out.println("Holle JAVA");  //输出
 　　}
 }

import java.io.*; //引入io包

public class C {
  public static void main(String[] args) throws IOException {

    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
    
    System.out.printf("请输入第一个数：");
    //接收第一个数
    String a = br.readLine();
    
    System.out.printf("请输入第二个数：");
    //接收第一个数
    String b = br.readLine();
    
    //String 转换 float
    float num1 = Float.parseFloat(a);
    float num2 = Float.parseFloat(b);

    System.out.println("a+b=" +(num1+num2));
    System.out.println("a-b=" +(num1-num2));
    System.out.println("a*b=" +(num1*num2));
    System.out.println("a/b=" +(num1/num2));
  }
}