From QB64 Wiki
The ASC statement allows a QB64 program to change a character at any position of a predefined STRING.
- ASC(string_expression$[, position%]) = code%
- The string expression variable must have been previously defined and cannot be an empty string("").
- The position parameter is optional. If no position is used, the left-most position(1) is assumed.
- The position cannot be zero or greater than the string's length LEN or an Illegal function error will occur.
- The ASCII replacement code% value can be any INTEGER value from 0 to 255.
- Some ASCII control characters will not PRINT a character or may format the SCREEN. _PRINTSTRING can print them graphically.
Example: Demonstrates how to change existing text characters one letter at a time.
ABC A C ASC