简体   繁体   中英

How can I check if a char is empty in Objective-C?

I need to test if a property is empty or not. It's declared like this in my header file:

@property (nonatomic) char nextOperation;

And in the .m file:

@synthesize nextOperation;

Correct me if I'm doing anything wrong, I'm pretty new in this world.

In a method I have to test if nextOperation has anything on it. If true ( YES ?) I should do something, and after that assign a new value to that property.

I've tried nextOperation == '' , empty , isEmpty , isempty , and everything throws me an Xcode warning/error.

A char can not be empty. A char is a scalar value just like an int - just a little smaller (usually 8 bit). You might want to compare it to 0 or 0x00 for your purpose.

eg

if (!self.nextOperation)
{
    //empty nextOperation
}
else
{
    //we got something in nextOperation
}

Try this:

if (self.nextOperation == 0) {
    // it's empty
}

or simply

if (!self.nextOperation) {
}

When you declare a property like that (without explicitly declaring an ivar or using @synthesize ) you can access the property using the dot syntax ( self.property ) or use the automatically generated ivar that starts with an underscore ( _property ).

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM