c concatenate strings

To concatenate strings in Objective-C, you can use the stringByAppendingString: method. This method appends a given string to the end of the receiver and returns a new string.

Here's an example of concatenating two strings in Objective-C:

NSString *string1 = @"Hello, ";
NSString *string2 = @"World!";
NSString *concatenatedString = [string1 stringByAppendingString:string2];

In this example, the stringByAppendingString: method is used to append string2 to the end of string1, resulting in Hello, World! being stored in concatenatedString.

You can also use the stringWithFormat: method to concatenate strings with other values, like variables or constants. This method allows you to format your strings using placeholders.

Here's an example of concatenating a string with a variable using stringWithFormat::

NSString *name = @"John";
NSString *greeting = [NSString stringWithFormat:@"Hello, %@", name];

In this example, the %@ placeholder is used to indicate where the name variable should be inserted in the formatted string.

These are the basic ways to concatenate strings in Objective-C using the stringByAppendingString: and stringWithFormat: methods.