i++ 和 ++i

深碍√TFBOYSˉ_ 2022-09-04 10:40 229阅读 0赞

### 文章目录 ###

*   *  方法
     *  1
     *  2
     *  3
     *  4

## 方法 ##

javac ClassName.java  
javap -c ClassName.class

## 1 ##

public class JavaTest1 { 
    
        public static void main(String[] args) { 
            test1();
        }
    
       public static void test1(){ 
            int a=0;
            int b=0;
            for(int j=0;j<2;j++){ 
                a=a++;
                System.out.print(a+"-");
    
                b=a++;
                System.out.println(b);
            }
            System.out.print(a+"-");
            System.out.println(b);
    
        }
    
    }

0-0  
1-1  
2-1

C:\Users\*\Desktop>javap -c JavaTest1.class
    Compiled from "JavaTest1.java"
    public class JavaTest1 {
      public JavaTest1();
        Code:
           0: aload_0
           1: invokespecial #1                  // Method java/lang/Object."<init>":
    ()V
           4: return
    
      public static void main(java.lang.String[]);
        Code:
           0: invokestatic  #2                  // Method test1:()V
           3: return
    
      public static void test1();
        Code:
           0: iconst_0
           1: istore_0
           2: iconst_0
           3: istore_1
           4: iconst_0
           5: istore_2
           6: iload_2
           7: iconst_2
           8: if_icmpge     59
          11: iload_0
          12: iinc          0, 1
          15: istore_0
          16: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          19: new           #4                  // class java/lang/StringBuilder
          22: dup
          23: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          26: iload_0
          27: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          30: ldc           #7                  // String -
          32: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          35: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          38: invokevirtual #10                 // Method java/io/PrintStream.print:
    (Ljava/lang/String;)V
          41: iload_0
          42: iinc          0, 1
          45: istore_1
          46: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          49: iload_1
          50: invokevirtual #11                 // Method java/io/PrintStream.printl
    n:(I)V
          53: iinc          2, 1
          56: goto          6
          59: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          62: new           #4                  // class java/lang/StringBuilder
          65: dup
          66: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          69: iload_0
          70: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          73: ldc           #7                  // String -
          75: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          78: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          81: invokevirtual #10                 // Method java/io/PrintStream.print:
    (Ljava/lang/String;)V
          84: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          87: iload_1
          88: invokevirtual #11                 // Method java/io/PrintStream.printl
    n:(I)V
          91: return
    }

## 2 ##

public class JavaTest2 { 
    
        public static void main(String[] args) { 
            test2();
        }
    
    
        public static void test2(){ 
            int a=0;
    
            for(int j=0;j<2;j++){ 
                a=a++;
                System.out.println(a+"-");
    
            }
            System.out.println(a+"-");
    
        }
    
    
    
    }

0-  
0-  
0-

C:\Users\*\Desktop>javap -c JavaTest2.class
    Compiled from "JavaTest2.java"
    public class JavaTest2 {
      public JavaTest2();
        Code:
           0: aload_0
           1: invokespecial #1                  // Method java/lang/Object."<init>":
    ()V
           4: return
    
      public static void main(java.lang.String[]);
        Code:
           0: invokestatic  #2                  // Method test2:()V
           3: return
    
      public static void test2();
        Code:
           0: iconst_0
           1: istore_0
           2: iconst_0
           3: istore_1
           4: iload_1
           5: iconst_2
           6: if_icmpge     45
           9: iload_0
          10: iinc          0, 1
          13: istore_0
          14: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          17: new           #4                  // class java/lang/StringBuilder
          20: dup
          21: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          24: iload_0
          25: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          28: ldc           #7                  // String -
          30: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          33: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          36: invokevirtual #10                 // Method java/io/PrintStream.printl
    n:(Ljava/lang/String;)V
          39: iinc          1, 1
          42: goto          4
          45: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          48: new           #4                  // class java/lang/StringBuilder
          51: dup
          52: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          55: iload_0
          56: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          59: ldc           #7                  // String -
          61: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          64: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          67: invokevirtual #10                 // Method java/io/PrintStream.printl
    n:(Ljava/lang/String;)V
          70: return
    }

## 3 ##

public class JavaTest3 { 
    
        public static void main(String[] args) { 
            test3();
        }
    
    
        public static void test3(){ 
            int a=0;
    
            for(int j=0;j<2;j++){ 
                a=++a;
                System.out.println(a+"-");
    
            }
            System.out.println(a+"-");
        }
    }

1-  
2-  
2-

C:\Users\*\Desktop>javap -c JavaTest3.class
    Compiled from "JavaTest3.java"
    public class JavaTest3 {
      public JavaTest3();
        Code:
           0: aload_0
           1: invokespecial #1                  // Method java/lang/Object."<init>":
    ()V
           4: return
    
      public static void main(java.lang.String[]);
        Code:
           0: invokestatic  #2                  // Method test3:()V
           3: return
    
      public static void test3();
        Code:
           0: iconst_0
           1: istore_0
           2: iconst_0
           3: istore_1
           4: iload_1
           5: iconst_2
           6: if_icmpge     45
           9: iinc          0, 1
          12: iload_0
          13: istore_0
          14: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          17: new           #4                  // class java/lang/StringBuilder
          20: dup
          21: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          24: iload_0
          25: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          28: ldc           #7                  // String -
          30: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          33: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          36: invokevirtual #10                 // Method java/io/PrintStream.printl
    n:(Ljava/lang/String;)V
          39: iinc          1, 1
          42: goto          4
          45: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          48: new           #4                  // class java/lang/StringBuilder
          51: dup
          52: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          55: iload_0
          56: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          59: ldc           #7                  // String -
          61: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          64: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          67: invokevirtual #10                 // Method java/io/PrintStream.printl
    n:(Ljava/lang/String;)V
          70: return
    }

## 4 ##

public class JavaTest4 { 
    
        public static void main(String[] args) { 
            test4();
        }
    
        public static void test4(){ 
            int a=0;
            int b=0;
    
            for(int j=0;j<2;j++){ 
                a=++a;
                b=a++;
                System.out.print(a+"-");
                System.out.println(b);
    
            }
            System.out.print(a+"-");
            System.out.println(b);
    
        }
    
    }

2-1  
4-3  
4-3

C:\Users\*\Desktop>javap -c JavaTest4.class
    Compiled from "JavaTest4.java"
    public class JavaTest4 {
      public JavaTest4();
        Code:
           0: aload_0
           1: invokespecial #1                  // Method java/lang/Object."<init>":
    ()V
           4: return
    
      public static void main(java.lang.String[]);
        Code:
           0: invokestatic  #2                  // Method test4:()V
           3: return
    
      public static void test4();
        Code:
           0: iconst_0
           1: istore_0
           2: iconst_0
           3: istore_1
           4: iconst_0
           5: istore_2
           6: iload_2
           7: iconst_2
           8: if_icmpge     59
          11: iinc          0, 1
          14: iload_0
          15: istore_0
          16: iload_0
          17: iinc          0, 1
          20: istore_1
          21: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          24: new           #4                  // class java/lang/StringBuilder
          27: dup
          28: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          31: iload_0
          32: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          35: ldc           #7                  // String -
          37: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          40: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          43: invokevirtual #10                 // Method java/io/PrintStream.print:
    (Ljava/lang/String;)V
          46: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          49: iload_1
          50: invokevirtual #11                 // Method java/io/PrintStream.printl
    n:(I)V
          53: iinc          2, 1
          56: goto          6
          59: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          62: new           #4                  // class java/lang/StringBuilder
          65: dup
          66: invokespecial #5                  // Method java/lang/StringBuilder."<
    init>":()V
          69: iload_0
          70: invokevirtual #6                  // Method java/lang/StringBuilder.ap
    pend:(I)Ljava/lang/StringBuilder;
          73: ldc           #7                  // String -
          75: invokevirtual #8                  // Method java/lang/StringBuilder.ap
    pend:(Ljava/lang/String;)Ljava/lang/StringBuilder;
          78: invokevirtual #9                  // Method java/lang/StringBuilder.to
    String:()Ljava/lang/String;
          81: invokevirtual #10                 // Method java/io/PrintStream.print:
    (Ljava/lang/String;)V
          84: getstatic     #3                  // Field java/lang/System.out:Ljava/
    io/PrintStream;
          87: iload_1
          88: invokevirtual #11                 // Method java/io/PrintStream.printl
    n:(I)V
          91: return
    }