GOTO

From C64-Wiki

BASIC keyword
Keyword:	GOTO
Abbreviation:	G Shift+O
Type:	Command
Token code:	137/$89
Handling routine in BASIC ROM:	43168–43217 $A8A0–A8D1
List of all BASIC keywords

Remark: This article describes the BASIC-Command GOTO in BASIC V2 at the Commodore 64.

Typ: Command
General Programming-Syntax: GOTO <line>

The BASIC command GOTO makes the BASIC interpreter jump to the indicated line and the execution of the BASIC program is continued at that line.

With the BASIC command GOTO infinite loops can be programmed. The code 55 GOTO 55 can only be stopped by pushing the key <RUN/STOP>.

The BASIC command GOTO can be used directly to start a programm at a specified line number like the BASIC command RUN <line>. Difference is that RUN clears variable values before starting the program, which GOTO does not.

When the targeted line number doesn't exist, the BASIC error ?UNDEF'D STATEMENT ERROR IN line occurs.

[edit] Examples

10 C=0: PRINT CHR$(147);: INPUT "Input a number, please "; A
20 PRINT "Input a second number, please "; 
30 INPUT B: IF C=1 AND B=0 GOTO 30
31 IF C=1 AND B<>0 GOTO 74
40 C=1: INPUT "Input an arithmetic operator (+-/*) "; A$
50 IF A$<>"+" OR A$<>"-" OR A$<>"*" OR A$<>"/" GOTO 30
60 IF B=0 AND A$="/" THEN PRINT "Division by 0 is not allowed, correction:";: GO TO 30
70 IF A$="+" THEN C=A+B: B$="ADDITION"
71 IF A$="-" THEN C=A-B: B$="SUBTRACTION"
72 IF A$="*" THEN C=A*B: B$="MULTIPLICATION"
73 IF A$="/" THEN C=A/B: B$="DIVISION"
74 PRINT "Your choice: " B$
75 PRINT "The output is: " C
80 INPUT "Another calculation (Y=YES, End with other chars)"; A$
90 IF A$="Y" THEN GOTO 10

Demonstration of direct GOTO vs. RUN contrast:

10 INPUT A
20 PRINT A

A=7:GOTO20
7

READY.
A=7:RUN20
0

READY.