Pascal - goto Statement

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A goto statement in Pascal provides an unconditional jump from the goto to a labeled statement in the same function.

NOTE: Use of goto statement is highly discouraged in any programming language because it makes difficult to trace the control flow of a program, making the program hard to understand and hard to modify. Any program that uses a goto can be rewritten so that it doesn't need the goto.

Syntax:

The syntax for a goto statement in Pascal is as follows:

goto label;
   ...
   ...
label: statement;

Here, label must be an unsigned integer label, whose value can be from 1 to 9999.

Flow Diagram:

Pascal goto statement

Example:

The following program illustrates the concept.

program exGoto;
label 1; 
var
   a : integer;
begin
   a := 10;
   (* repeat until loop execution *)
   1: repeat
      if( a = 15) then
      begin
         (* skip the iteration *)
         a := a + 1;
         goto 1;
      end;
      writeln('value of a: ', a);
      a:= a +1;
   until a = 20;
end.

When the above code is compiled and executed, it produces the following result:

value of a: 10
value of a: 11
value of a: 12
value of a: 13
value of a: 14
value of a: 16
value of a: 17
value of a: 18
value of a: 19

Please note that:

  • In Pascal, all labels must be declared before constant and variable declarations.

  • The if and goto statements may be used in the compound statement to transfer control out of the compound statement, but it is illegal to transfer control into a compound statement.



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