The following code produces a "lvalue required as left operand of assignment"
if( c >= 'A' && c <= 'Z' || c = " " || c = ",") {
I assume I'm writing this wrong, what is wrong? and how would I write it correctly?
4 Answers
You should use single quotes for chars and do double equals for equality (otherwise it changes the value of c)
if( c >= 'A' && c <= 'Z' || c == ' ' || c == ',') {
Furthermore, you might consider something like this to make your boolean logic more clear:
if( (c >= 'A' && c <= 'Z') || c == ' ' || c == ',') {
Although your boolean logic structure works equivalently (&& takes precedence over ||), things like this might trip you up in the future.
answered Jun 16, 2010 at 1:23
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2FWIW, I'd use
('A' <= c && c <= 'Z')to make that bit of logic clearly show that 'A' and 'Z' are the 'outer' bounds and have the expression most resemble the math-style 'A' <= c <= 'Z' Commented Jun 16, 2010 at 2:00
equality is ==, = is assignment. You want to use ==. Also "" is a char*, single quotes do a character.
Also, adding some parens to your condition would make your code much easier to read. Like so
((x == 'c' && y == 'b') || (z == ',') || (z == ' '))
= is the assigning operator, not the comparing operator. You are looking for ==.
Personally, I prefer the minimalist style:
((x == 'c' && y == 'b') || (z == ',') || (z == ' '))
( x == 'c' && y == 'b' || z == ',' || z == ' ' )
or
( x == 'c' && y == 'b' ? z == ',' : z == ' ' )
against
( x == 'c' && y == 'b' ? z == ',' : z == ' ')
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!!! the html washine has skipped the dubble space around logical operators !!!! --- and that makes all the visible difference ---– billCommented Mar 20, 2015 at 14:39
cis a macro that expands to a non-lvalue. Ifcis declared as a plain variable,c = " "should produce "incompatible types in assignment" or something similar. My guess is that in your actual code you're usingf() = " "(i.e., a function's return value instead ofc).