To convert string values to numeric values.
CVI(2-byte string)
CVS(4-byte string)
CVD(8-byte string)
Numeric values read in from a random-access disk file must be converted from strings back into numbers if they are to be arithmetically manipulated.
CVI converts a 2-byte string to an integer. MKI$ is its complement.
CVS converts a 4-byte string to a single-precision number. MKS$ is its complement.
CVD converts an 8-byte string to a double-precision number. MKD$ is its complement.
70 FIELD #1, 4 AS N$, 12 AS B$...
80 GET #1
90 Y=CVS(N$)
Line 80 reads a field from file #1 (the field read is defined in the first line), and converts the first four bytes (N$) into a single-precision number assigned to the variable Y.
Since a single-precision number can contain as many as seven ASCII characters (seven bytes), writing a file using MKS$ conversion, and reading with the CVS conversion, as many as three bytes per number recorded are saved on the storage medium. Even more may be saved if double-precision numbers are required. MKD$ and CVD conversions would be used in this case.