Calculation of string length in Objective-c

We know that in C, using sizeof () to calculate the number of bytes occupied in the memory, after referencing string.h, use strlen () to calculate the length of the string (not including).

In Object-c, the "Length" method can return the length of a string.

For example: NSString * str =@ "12345"; int a = 0; A = [str lenght]; At this point the value of a is the length of the string str, which is 5.

It is worth mentioning that the length method in OC in the calculation of string lengths and C there are several differences, in C, if the string has a Chinese character is calculated by three bytes of length, such as char * str = "haha"; the length of this string is 6, but in OC, The length of each symbol is 1 regardless of whether the string is in Chinese or other characters, for example: NSString * str = @ "haha"; then the length of STR is 2.

Let's take a few examples to better understand:

1) string length calculation in pure English:

NSString *str = @ "Wanghy";

Nsuinteger len = [str length];

The value of Len at this time is 6.

NSLog (@ "len =%ld", Len);

2) length calculation of strings in pure Chinese

Each Chinese character is treated as a single character

NSString *STR2 = @ "The world is so big, I want to see";

len = [str2 length];

The value of Len should be 11.

NSLog (@ "len =%ld", Len);

3) mixed in Chinese and English

Summary: Whether Chinese or English, in OC is considered to be a character

NSString *STR3 = @ "haha itcast";

len = [STR3 length];

NSLog (@ "len =%ld", Len); Len = 10;