Environmental Ubuntu18.04 GCC 8.40 unable to compile the 32-bit program

Online tutorial https://blog.csdn.net/longintchar/article/details/50557832

And I follow the tutorial

Is this error

Baidu still say this said this problem did not obey the orders of the tutorial I'm sure carried out to perform a few times so it is

Mainly like to do some questions many times to perform in a 32-bit environment such as a pointer class size such as length o is the premise on a 32-bit environment