Array中放若干String 按首字母排序输出

self.arr = [[NSMutableArray alloc] initWithObjects:@"Tom", @"Cat", @"Jarry", @"mouse", @"Amy", nil];
for (int i = 0; i < 5; i++) {
for (int j = 0; j < 5 -i -1; j++) {
if ([self.arr[j] compare:self.arr[j+1]] == NSOrderedDescending) {
NSString * temp = self.arr[j];
self.arr[j] = self.arr[j+1];
self.arr[j+1] = temp;

        }
    }
}
NSLog(@"%@",self.arr);