75 70 G=RND(12) 80 PRINT "WHAT IS ";F;" TIMES "G; 90 INPUT H 100 IF H=F*G THEN PRINT "CORRECT" ELSE PRINT "WRONG" 110 PRINT 120 UNTIL TIME-STARTTIME>1500 130 PRINT "TIME UP" >RUN SEE HOW MANY SUMS YOU CAN DO IN 15 SECONDS WHAT IS 6 TIMES 9?72 WRONG WHAT IS 1 TIMES 4?4 CORRECT WHAT IS 9 TIMES 8?72 CORRECT TIME UP REPEAT...UNTIL loops are very useful and should be used frequently. The next program selects random letters (line 20) and times how long it takes you to find and press the appropriate key. It uses two REPEAT...UNTIL loops. One of them is used to wait for a particular key to be pressed on the keyboard.
10 REPEAT 20 Z=RND(26)+64 30 PRINT 40 PRINT "PRESS THE KEY MARKED ";CHR$(Z) 50 T=TIME 60 REPEAT UNTIL GET=Z 70 PRINT "THAT TOOK YOU"(TIME-T)/100" SECONDS" 80 UNTIL Z=0 >RUN PRESS THE KEY MARKED Y THAT TOOK YOU 1.1 SECONDS PRESS THE KEY MARKED G THAT TOOK YOU 1.03 SECONDS Lines 10 and 80 are the main loop and line 60 is a single line REPEAT UNTIL loop.