在面试中，经常被问到字符串倒序的面试题，下面提供两种简单的实现：
第一种：
- (NSString*)reverseWordsInString:(NSString*)oldStr{
NSMutableString *newStr = [[NSMutableString alloc] initWithCapacity:oldStr.length];
for (int i = (int)oldStr.length - 1; i >= 0; i --) {
unichar character = [oldStr characterAtIndex:i];
[newStr appendFormat:@"%c",character];
}
return newStr;
}
第二种：
- (NSString*)reverseWordsInString:(NSString*)oldStr
{
NSMutableString *newStr = [NSMutableString stringWithCapacity:oldStr.length];
[str enumerateSubstringsInRange:NSMakeRange(0, oldStr.length) options:NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop){
[newStr appendString:substring];
}];
return newStr;
}
