C: Error in Using: "Compound Assignment" and "Prefix Decrement" together

Question

Can someone please tell me why the C compiler outputs an error while using a Compound Assignment and a Prefix Dec/Inc together ? [ but C++ does not ]

int myVar = 5;
(--myVar) -= 4;
// C  : error C2106: '-=' : left operand must be l-value
// C++: myVar=0;

I know what the error says ...

But, I can't understand why a C compiler can't recognize myVar as a l-value but C++ does?!

myVar is lvalue, --myVal is not lvalue, simple as that – Creris May 05 '15 at 15:11 — Creris, May 05 '15 at 15:11

haccks · Accepted Answer · 2015-05-06T18:07:36.160

6

In C, prefix -- operator yields an rvalue. An rvalue can't be a left operand of assignment operator. That said, C and C++ are two different languages.

edited May 06 '15 at 18:07

answered May 05 '15 at 15:12

haccks

104,019
25
176
264

assignment would be more specific, since there are quite a few ways to assign into integer – Creris May 05 '15 at 15:13

C: Error in Using: "Compound Assignment" and "Prefix Decrement" together

1 Answers1