QBASIC program to produce bar charts or Histograms?

Check out this QBASIC program to produce a bar chart from inputted data.

CLS
SCREEN 12
' THIS PROGRAM PLOTS A BAR CHART OF 12 BARS

INPUT " CHOOSE THE COLOR OF YOUR BARS,ANY ONE OF BLUE, GREEN, RED AND
YELLOW"; COL$

SELECT CASE COL$
CASE "BLUE"
LET A = 9
CASE "GREEN"
LET A = 10
CASE "RED"
LET A = 12
CASE "YELLOW"
LET A = 14
CASE "blue"
LET A = 9
CASE "green"
LET A = 10
CASE "red"
LET A = 12
CASE "yellow"
LET A = 14

END SELECT
LINE (10, 200)-(10, 400)
LINE (10, 400)-(600, 400)

FOR X = 35 TO 600 STEP 50
INPUT "INPUT VERTICAL VALUE <= 200 "; Y
LINE (X, (400 - Y))-((X + 30), 400), A, BF
NEXT X

END