Objective-C 類型

1. Strings

1) 簡單字串

NSString *aString = @"this is a string";NSString *anotherString = @"and this is another one";

2) 對象初始化

NSString *aString = [[NSString alloc] initWithString:@"some string literal"];NSString *aString = [NSString stringWithString:@"some string literal"];

3) 格式化字串

int theValueOfPi = 3;//produces the string "pi is exactly 3!"NSString *aString = [NSString stringWithFormat:@"pi is exactly %d!", theValueOfPi];

4) 對象格式化

NSString *aString = @"criminals";NSString *anotherString = [NSString stringWithFormat:@"When you %@ strings, only %@ willuse strings.", @"criminalize", aString];

5) 字串比較

NSString *aString = @"hello";NSString *anotherString = @"hello";BOOL stringsAreEqual = ([aString isEqualToString:anotherString]);

BOOL stringsAreEqual = (aString == anotherString); //這是錯誤的