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int i = 3;
int j = (i)++;
vs
int i = 3;
int j = i ++;
Is there a difference between how the above two cases are evaluated?
Is the first case equivalent to incrementing an rvalue or is it undefined behaviour?
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answer i++ means post increment it means first the value of i is printed and then incremented. ++i means pre increment it means first value is incremented and then printed. i++ means post increment it means first the value of i is printed and then incremented.
What is the difference between ++i and i++ in C++? There is a big distinction between the suffix and prefix versions of ++. In the prefix version (i.e., ++i), the value of i is incremented, and the value of the expression is the new value of i. So basically it first increments then assigns a value to the expression.
i = i+1 will increment the value of i, and then return the incremented value. i++ will increment the value of i, but return the original value that i held before being incremented.
In C, ++ and -- operators are called increment and decrement operators. They are unary operators needing only one operand. Hence ++ as well as -- operator can appear before or after the operand with same effect. That means both i++ and ++i will be equivalent. i=5; i++; printf("%d",i);
i++ and (i)++ behave identically. C 2018 6.5.1 5 says:
A parenthesized expression is a primary expression. Its type and value are identical to those of the unparenthesized expression. It is an lvalue, a function designator, or a void expression if the unparenthesized expression is, respectively, an lvalue, a function designator, or a void expression.
The wording is the same in C 1999.
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In your simple example of i++ versus (i)++, there is no difference, as noted in Eric Postpischil's answer.
However, this difference is actually meaningful if you are dereferencing a pointer variable with the * operator and using the increment operator; there is a difference between *p++ and (*p)++.
The former statement dereferences the pointer and then increments the pointer itself; the latter statement dereferences the pointer then increments the dereferenced value.
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