QBASIC PROGRAM TO FIND SUM OF DIGITS(SUB)

DECLARE SUB SUM(N)
CLS
INPUT "ENTER ANY NUMBER";N
CALL SUM(N)
END

SUB NUM(N)
S=0
WHILE N<>0
R= N MOD 10
S=S+R
N=N\10
WEND
PRINT"SUM OF DIGITS";S
END SUB