Hi,
CAn anyone tell me what does the following statement do in C. *p++ = val My understanding is that because ++ and * have right-associativity, it is equivalent to
p++;
*p=val;Similarly val = *--p is equivalent to
p--;
val = *p;Is it correct?
How about writing a test program to test your assertions?
Hi,
CAn anyone tell me what does the following statement do in C.*p++ = val
*p is assigned the value of val and then p is incremented.
My understanding is that because ++ and * have right-associativity
Associativity? I don't even think you got that right if you were trying to say precedence.
Similarly
val = *--p
p is decremented and then val is assigned the value of *p .
and you can also use while(*p++) it will increment addr till it meet \0 in a char *
Associativity? I don't even think you got that right if you were trying to say precedence.
Isn't the precedence of * and ++ same, that's why we look for the associativity in *p++ whcih is right to left.
>Associativity? I don't even think you got that right if you were trying to say precedence.
Nope. He got it right, but came to the wrong conclusion. ++ and * (dereference) have the same precedence but are right associative, so ++ is indeed performed first. However, one can't forget that the postfix increment operator evaluates to the value prior to the increment, and the increment itself is a side effect. Thus the expression *p++ = val; is equivalent to:
*p = val;
++p;This can easily be verified by using the prefix increment in the same order. *++p = val; is equivalent to:
++p;
*p = val;Perhaps it was just the chart I was looking at the showed postfix at higher precedence than prefix.
Perhaps it was just the chart I was looking at the showed postfix at higher precedence than prefix.
Isn't this another case were we should not depend in the order of precedence between sequence points?
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