IOS changes the case sensitivity of letters.

IOS changes the case sensitivity of letters.

Use lowercaseString and uppercaseString

- (void)test{    NSString *testString = @"Hello World";        // lower case    NSString *lowerCaseString1 = [testString lowercaseString];    NSString *lowerCaseString2 = testString.lowercaseString;        // upper case    NSString *upperCaseString1 = [lowerCaseString1 uppercaseString];    NSString *upperCaseString2 = lowerCaseString1.uppercaseString;        NSLog(@"lowerCaseString1: %@",lowerCaseString1);    NSLog(@"lowerCaseString2: %@",lowerCaseString2);    NSLog(@"upperCaseString1: %@",upperCaseString1);    NSLog(@"upperCaseString2: %@",upperCaseString2);        // capitalize the first word of the sentence    NSString *txt = @"hi my friends!";    txt = [txt stringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[txt substringToIndex:1] uppercaseString]];    NSLog(@"txt: %@", txt);}

Print result:

2014-08-26 17:00:30.266 MyApp[68821:60b] lowerCaseString1: hello world2014-08-26 17:00:30.267 MyApp[68821:60b] lowerCaseString2: hello world2014-08-26 17:00:30.267 MyApp[68821:60b] upperCaseString1: HELLO WORLD2014-08-26 17:00:30.267 MyApp[68821:60b] upperCaseString2: HELLO WORLD2014-08-26 17:00:30.268 MyApp[68821:60b] txt: Hi my friends!

Reference Source:

Http://stackoverflow.com/questions/8693741/converting-all-text-to-lower-case-in-objective-c

Http://stackoverflow.com/questions/2432452/how-to-capitalize-the-first-word-of-the-sentence-in-objective-c