//集合中,不能存储基本数据类型,如果你想要把基本数据类型存储到数组,集合中,就必须把它转换成基本数据类型的包装类    @autoreleasepool {      //int float double char        int a = 10;//        [NSString stringWithFormat:@"%d",a];                //1.使用NSNumber 包装  int数据类型        NSNumber * number1 = [NSNumber numberWithInt:a];        NSLog(@"%@",number1);                //2.直接转换成字符串        NSString * strInt = [number1 stringValue];        NSLog(@"strInt %@",strInt);                //3.float包装成NSNumber        NSNumber * number2 = [NSNumber numberWithFloat:98.98];        NSLog(@"number2 %@",[number2 stringValue]);                //4.包装类转换成基本数据类型                int b  = [number1 intValue];        NSLog(@"%d",b);    }    return 0;