A for-do loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.
The syntax for the for-do loop in Pascal is as follows:
for:= to [down to] do S;
Where, the variable-name specifies a variable of ordinal type, called control variable or index variable; initial_value and final_value values are values that the control variable can take; and S is the body of the for-do loop that could be a simple statement or a group of statements.
For example,
for i:=1 to 10 do writeln(i);
Here is the flow of control in a for-do loop:
program forLoop; var a: integer; begin for a :=10 to 20 do begin writeln('value of a: ', a); end; end.
When the above code is compiled and executed, it produces 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: 15 value of a: 16 value of a: 17 value of a: 18 value of a: 19 value of a: 20