# how???

Discussion in 'C' started by IndiraP, Dec 12, 2012.

1. ### IndiraPNew Member

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I have seen this one in this forum only..but i couldnt understand how come the answer is 10 for the below ???

int z,x=5,y=-10,a=4,b=2;
z = x++ - --y * b / a;

then output of z..???

2. ### Rajesh M. KanojiaNew Member

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i think the value of z is 10.
how:-
step 1:- --y is evaluated which become -11.
step 2:- (-11) will multiple with b which become -22
step 3:- this (-22) get devided by a now intermidiate result will be -5
step 4:- now expression become as z=x++ - -5;
step 5 :- -5 become +5
step 6:- here the main game start the priority of post-increment is lower then assignement operater that's why first the value of x which is 5 is added with intermidiat result +5 which become 10 and this 10 get assigne into variable z .
step 7:- variable x increment its value by 1 and become 6.

3. ### IndiraPNew Member

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But ++, -- have higher precedence than / ,*..???

4. ### xpi0t0sMentor

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Don't forget that x++ means POSTincrement and ++x means PREincrement. That means before and after, and is usually before or after some execution point. So the equation in some senses (but definitely not all) is equivalent to:
Code:
```--y;
z = x - y * b / a;
x++;
```
This should be a lot easier to evaluate. First y is decremented to -11.
Then z=5 - -11 * 2 / 4
=5 - -22/4
=5 - -5
=5 + 5
=10.

Then x is incremented.

5. ### IndiraPNew Member

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Thank u sir...