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pre increment and post increment please help me out

hi everyone well i m little bit confused about the use of pre an post increment infact my thinking contradict with the logic of programe
lets consider an example
after the execution of these statments value of y will b 5 while value of z will be 6
value of x++ and x=x+1is equal it first assign a value of x to y then increment in x. why?
expression on the right must be executed first then it must assign value to y
mean to saty value of y must be 6 just like pre increment.
if not then what about the given expression
in this case why it is not assigning a value of x to y first and then solving expression?
although it first solve expression and then assign its value to y.
i m too much confuse about this please help me out
Nov 28 '06 #1
1 2077
1,510 Expert 1GB
the ++ and -- operators are prefix or postfix
(1) postfix (e.g. i++ or i--) the value of the operand is used in the expression then it is incremented or decremented.
(2) prefix (e.g. ++i or --i) the value of the operand is incremented or decremented and the new value used in the expression.

For example, assuming i = 10
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  1.    k = i++; after assignment k would = 10 and i = 11
  2.    k = ++i; after assignment k would = 11 and i = 11
Now, assuming i = 10 and j = 2 consider the expressions (which may be part of a larger expression):
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  1.    i * j++  result = 20, j = 3 (incremented after evaluation)
  2.    i * ++j  result = 30, j = 3 (incremented before evaluation)
  3.    i * j--  result = 20, j = 1 (decremented after evaluation)
  4.    i * --j  result = 10, j = 1 (decremented before evaluation)
does that help?

by the way don't do
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  1. i=i++;
you don't know if the ++ is done before or after the assignment - it is undefined
Nov 28 '06 #2

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