C语言 “左值需要作为赋值的左操作数”错误
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"lvalue required as left operand of assignment " error
提问by Skizit
The following code produces a "lvalue required as left operand of assignment"
下面的代码产生一个“左值需要作为赋值的左操作数”
if( c >= 'A' && c <= 'Z' || c = " " || c = ",") {
I assume I'm writing this wrong, what is wrong? and how would I write it correctly?
我想我写错了，有什么问题？我将如何正确编写它？
回答by Michael Chinen
You should use single quotes for chars and do double equals for equality (otherwise it changes the value of c)
您应该对字符使用单引号，并为相等使用双引号（否则它会更改 c 的值）
if( c >= 'A' && c <= 'Z' || c == ' ' || c == ',') {
Furthermore, you might consider something like this to make your boolean logic more clear:
此外，您可能会考虑这样的事情，以使您的布尔逻辑更加清晰：
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.
尽管您的布尔逻辑结构等效地工作（&& 优先于 ||），但这样的事情将来可能会绊倒您。
回答by Paul Rubel
equality is ==, =is assignment. You want to use ==. Also ""is a char*, single quotes do a character.
相等是==，=是赋值。您想使用==. 也是""一个char*，单引号做一个字符。
Also, adding some parens to your condition would make your code much easier to read. Like so
此外，在您的条件中添加一些括号会使您的代码更易于阅读。像这样
((x == 'c' && y == 'b') || (z == ',') || (z == ' '))
回答by Femaref
=is the assigning operator, not the comparing operator. You are looking for ==.
=是赋值运算符，而不是比较运算符。您正在寻找==.
回答by bill
Personally, I prefer the minimalist style:
就个人而言，我更喜欢极简风格：
((x == 'c' && y == 'b') || (z == ',') || (z == ' '))
( x == 'c' && y == 'b' || z == ',' || z == ' ' )
or
或者
( x == 'c' && y == 'b' ? z == ',' : z == ' ' )
against
反对
( x == 'c' && y == 'b' ? z == ',' : z == ' ')
