Blocks and Procedures in ADA

Blocks

A Block in ADA contains two parts specification and a body. The specification specifies the variable used inside the block and the body executes the statement for the block

syntax

block

begin

---

---

end

• The main purpose of blocks are information hiding.
  
• A Variable declared inside a block is accessible only within the block and nowhere outside the block.

Example

var x,y:integer

begin 

  y:=0;

 for x in 1..10 loop

  block

   var x:integer;

    begin 

    for x in 1..5 loop

    y:=y+x;

   end loop;

end;

end loop;

(NB: the above example shows two variables x within the block and outside the block, The x inside the block is accessible only within that block)

Procedures and Functions

1. Blocks are repeated whenever they are needed, but functions can be written once, called anytimes

Examples

//to define a function to show the smaller among two integers

function SMALLER (A,B: integer) return integer is 

begin

if A < B then

  return A;

else

return B;

end if;

end SMALLER;

//function calling SMALLER

D:=C+SMALLER(x,y);