for循环j = j++ 和 j = ++j

package com.test.forname;

public class TestForName {
public static void main(String[] args) throws Exception{

/* A a = (A) Class.forName("com.test.a.A").newInstance();
Class<?> c = Class.forName("com.test.c.C");
System.out.println(a.getClass());
System.out.println(c.getClasses());
System.out.println(c.getClassLoader());*/

int j = 0;
for(int i=0;i<100;i++){
j = j++;
}
System.out.print(j);

}

运行结果：0

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package com.test.forname;

import com.test.a.A;
import com.test.c.C;

public class TestForName {
public static void main(String[] args) throws Exception{

/* A a = (A) Class.forName("com.test.a.A").newInstance();
Class<?> c = Class.forName("com.test.c.C");
System.out.println(a.getClass());
System.out.println(c.getClasses());
System.out.println(c.getClassLoader());*/

int j = 0;

j = j++  Java用了中间缓存变量的机制，等同于

temp = j;

j = j + 1;

j = temp;

for(int i=0;i<100;i++){

j = ++j;

}
System.out.println(j);

}

}

输出结果：100

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int j = 0,k = 0;
for(int i=0;i<3;i++){
j = j++;

k = j++ + ++j;

if(i == 2){
System.out.println("j-"+j++);
}
}
System.out.println("j---"+j);
System.out.println("k---"+k);
}

输出结果：

j-6
j---7
k---10

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