1. The numbers we know are numbers, not characters. Numbers are virtual. Characters are converted from numbers. To learn strings, we must understand ASCII interchange codes.

2. The string is actually an array, but it has no pointer. Because any position of the string can be modified, if the value of the pointer is 1, then the character at 1 may not be what you want. It may be influenced by several processes and functions of a string, such as length.

After assigning a value to a string, such as "123456", you can use [i]:= to assign a value. But when the length is uncertain, that is, when the string is empty, the pointer should be useless. The allocation string must use characters. Using chr+ord has no effect on plastic operation. It turned out to be plastic. Another thing to be reminded is that the order code of .0 is 48.

If you want to convert numbers into characters, it will be better to use processes.

Str(value, st) converts a numeric string value into a numeric string st.