beginner in java

As i am a beginner in java.i could not understand this program.this is a simple program of postfix and prefix increment operator.but i could not understand the output of this program.i understand the output of variable c and d but the output of a and b confuses me.if somebody please help me.pls help me so that i can move forward in java.thank you.

class in
public static void main(String args[])
int a = 3;
int b = 7;
int c = a++;
int d = ++b;
System.out.println("a = "+a);
System.out.println("b = "+b);
System.out.println("c = "+c);
System.out.println("d = "+d);

output is
a = 4
b = 8
c = 3
d = 8


  • In a postfix usage, the value of a is assigned to c, then incremented by one. In the prefix usage, the value of b is incremented, then assigned to d.
  • sir,
    i also knew this but my question is that why the values of a and b incremented despite the fact we don't use any increment operator with both these variables.please explain me the outcome of the following code:
    System.out.println("a = "+a);
    System.out.println("b = "+b);
    why the outcome of this code is:
    a = 4;
    b = 8;
    i am very grateful to you.if you or anybody explain this.

  • tarun01,
    The add 1 prefix and postfix operator is, ++ (notice it is [b]two + signs[/b]). Their location before, prefix, or after, postfix, a variable determine when the value of the variable is incremented by one.

    The postfix and prefix operations on the variables occurs in these lines:
    int c = a++; // c is assigned value of a, 3, then a is incremented by 1
    int d = ++b; // b is incremented by 1, then d is assigned value of b [/code]
    What happens in these lines
    System.out.println("a = "+a);
    System.out.println("b = "+b);[/code]
    is that the variables are printed. The [b]single + sign[/b] in these expressions is a [b]concatenation operator[/b] that unites the strings on both sides of the + sign.
  • do not need to worry

    first your a=3 then in your program your given c=a++

    here a++ is post increment in a++ a value become 4
    and it is assigned after so a=4 and c=3

  • Ok, I'm new to Java, but I think I got this.

    So what happens in this line:
    int c = a++; --> 'a' is now incremented to = 4

    So by the time we approach:
    System.out.println("a = "+a);
    --> you're getting "a =" (a String) + (concatenated) "+a" which is printing out the String form of "a", which because of the above statement now equals '4'.

    To prove, if you comment out the line:
    int c = a++;
    --> System.out.println("a = "+a); will produce a String output of: "a = 3"

    Something else to try is if you modify to:
    System.out.println("a = " + a + 1);
    --> you'll get '4'(String) + concatenated with '1' (String) with an output of: "a = 41)

    Hope this helps.
  • this is simple
    a++ is like a=a+1 so a=4
    and ++b is the same in this case but has other signification in other case
  • These things are avaiable in all major browsers
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