# Operator evaluation order

Alexan Kahkejian

Ranch Hand

Posts: 74

Saravanakumar Rajmohan

Greenhorn

Posts: 17

posted 13 years ago

x = -1

y= x++ + ++x

operands are always evaluated from left to right

before an operation is performed all the operands are

evaluated except in conditional operators such as (&& , || and in some cases of ?

then the operation is performed based on precedence

ans associativity.

before addition could be performed both the operand has to be

evaluated

Left operand

x++ is evaluated . since it is postfix expression the vlaue of the expression is the value of x before

the increment is performed. so the expression will get the value -1(which is the value of x before increment) but x will be incremented by one

so x will be -1+1=0.

Right operand

++x is evaluated . since it is prefixx expression the value of the expression is the value of x after

the increment is performed. so the expression will get the incremented value of x that is 1.

Left expression + Right expression

-1 + 1 = 0

so y=0

x =1

hope this helps

Saravanakumar R

y= x++ + ++x

operands are always evaluated from left to right

before an operation is performed all the operands are

evaluated except in conditional operators such as (&& , || and in some cases of ?

then the operation is performed based on precedence

ans associativity.

before addition could be performed both the operand has to be

evaluated

Left operand

x++ is evaluated . since it is postfix expression the vlaue of the expression is the value of x before

the increment is performed. so the expression will get the value -1(which is the value of x before increment) but x will be incremented by one

so x will be -1+1=0.

Right operand

++x is evaluated . since it is prefixx expression the value of the expression is the value of x after

the increment is performed. so the expression will get the incremented value of x that is 1.

Left expression + Right expression

-1 + 1 = 0

so y=0

x =1

hope this helps

Saravanakumar R

Emad Salahuddin

Greenhorn

Posts: 6

posted 13 years ago

Hello Alexan:

First the postfix and prefix operators are evaluated and the added together as they have higher precedence over addition.

So coming back to your question:

int x = -1;

y = x++ + ++x;

This would be evaluated as:

y = -1 + 1

y = 0

The postfix operator (x++) gets the value -1 first and then x is incremented by 1 to give 0.

The prefix operator (++x) adds 1 to x first, then uses the new value of x as the value of the expresiion.

Hope this helps.

Emad

First the postfix and prefix operators are evaluated and the added together as they have higher precedence over addition.

So coming back to your question:

int x = -1;

y = x++ + ++x;

This would be evaluated as:

y = -1 + 1

y = 0

The postfix operator (x++) gets the value -1 first and then x is incremented by 1 to give 0.

The prefix operator (++x) adds 1 to x first, then uses the new value of x as the value of the expresiion.

Hope this helps.

Emad