about ++

[zhang feng]

i have a class

 
 class Test
 { public static void main(String[] arg)
   {  int i=0;
      i=i++;
      System.out.println(i);
     }
   }
 

i dont understand , c++ will print 1; java print 0;
java development from c++ ,why the statement(i=i++)
print 0,and not 1;

[chi Lin]

there is some discussion here.

Originally posted by zhang feng:
i have a class

 
 class Test
 { public static void main(String[] arg)
   {  int i=0;
      i=i++;
      System.out.println(i);
     }
   }
 

i dont understand , c++ will print 1; java print 0;
java development from c++ ,why the statement(i=i++)
print 0,and not 1;

[Thomas Paul]

This discussion comes up a lot:
http://www.coderanch.com/t/242161/java-programmer-SCJP/certification/Unexpected-output
The two things to note are:
1) The behavior of this is undefined in C++. You may see one result in one compiler and another result in another compiler.
2) The postfix operator returns a result and then increments. So when you do i = i++, if i = 0 then you are getting:
a) return 0
b) increment i to 1
c) assign the returned value of 0 to i
Operator precedence says that postfix occurs before assignment.