iOS·数组元素逆序方案

strArr = [NSArray arrayWithObjects: @"a", @"b", @"c", @"d", @"e", nil];

NSMutableArray strRevArray = [NSMutableArray array];
int size = [strArr count];
int i;
if(size>1){
  i = size -1;
}else{
  i = 0;
}
for(i; i >=0; i--) {
    NSString *str = [strArr objectAtIndex:i]; 
    [strRevArray addObject:str];
}

NSArray *strRevArray = [[strArr reverseObjectEnumerator] allObjects];

NSMutableArray strRevArray = [NSMutableArray array];
for (NSString *str in [strArr reverseObjectEnumerator]) {
    [strRevArray addObject:str];
}

NSMutableArray strRevArray = [NSMutableArray array];
[strArr.reverseObjectEnumerator.allObjects enumerateObjectsUsingBlock:^(NSString  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
  [strRevArray addObject:str];
}];