Repetitions in Pascal with examples (while, for, repeat until)

Loops/Repetitions in Pascal with examples

Loops are used to execute certain parts of code (statements) for a specific number of times, or until a condition is satisfied.
There are three type of loops/repetitions available in pascal.
They are

• while
• for
• repeat … until

Pascal program to print one to hundred using “while”

program onetohundredwhile;
{define variable}
var
x: integer;
{main program}
begin {start of main program}
  {assign value to variable x}
  x:=1;
  while x<=100 do  {repeat until the condition is true}
  begin {start repetition}
       write(x,#9);
       x:=x+1;
  end; {end repetition}
  readln();
end.

Pascal program to print one to hundred using “for”

program onetohundredwhilefor; 
var
x: integer;
{main program}
begin
   for x:=1 to 100 do {no block since having one statement only}
      writeln(x);
  readln();
end.     {end of main program}           

Pascal program to print one to hundred using “repeat...until”

program onetohundredrepeatuntil;
var
x: integer;
begin {start of main program}
  x:=1;
  repeat {start repetition}
    writeln(x);
    x:=x+1;
  until x>100; {repeat until the condition is false}
  readln(); 
end.  {end of main program}           

Note :

• {} in pascal is used for comments, comments are not executed when program is compiled or executed.
• begin .... end; is used to make a block of statements
• readln() is used to wait until the enter key pressed to finish
• #9 for tab