procedure Str(const X; var S: string);
Formats a string and returns it to a variable.
In Delphi code, Str converts X to a string representation according to the Width and Decimals formatting parameters. The effect is similar to the one of a call to Write, except the resulting string is stored in S instead of being written to a text file.
X is an integer-type or real-type expression. Width and Decimals are integer-type expressions. S is a string-type variable or a zero-based character array variable, if extended syntax is enabled.