do while loop

A do while loop is a control flow statement that allows code to be executed repeatedly based on a given condition.

do while loop syntax

    do begin
        // statement -1       
        ...
        // statement -n 
    end
    while(condition);

In do-while,

• the condition will be checked after the execution of statements inside the loop
• the condition can be any expression.

do-while is similar to while loop but in case of while loop execution of statements happens only if the condition is true. In a do while, statements inside the loop will be executed at least once even if the condition is not satisfied.

do while loop example

module do_while;
  int a;
 
  initial begin
    $display("-----------------------------------------------------------------");

    do
      begin
        $display("\tValue of a=%0d",a);
        a++;
      end
    while(a<5);
  
    $display("-----------------------------------------------------------------");
  end    
endmodule

Simulator output:

-----------------------------------------------------------------
Value of a=0
Value of a=1
Value of a=2
Value of a=3
Value of a=4
-----------------------------------------------------------------

Click to execute on

do while loop example 2

module do_while;
  int a;
 
  initial begin
    $display("-----------------------------------------------------------------");
   
    do
      begin
        $display("\tValue of a=%0d",a);
        a++;
      end
    while(a>5);

    $display("-----------------------------------------------------------------");
  end
endmodule

Simulator Output

-----------------------------------------------------------------
Value of a=0
-----------------------------------------------------------------

Click to execute on

while loop SystemVerilog

A while loop is a control flow statement that allows code to be executed repeatedly based on a given condition.

while loop syntax

    while(condition) begin
        // statement -1       
        ...
        // statement -n 
    end

In a while,

• Execution of statements within the loop happens only if the condition is true

while loop example

module while_loop;
  int a;

  initial begin
    $display("-----------------------------------------------------------------");

    while(a<5)
      begin
        $display("\tValue of a=%0d",a);
        a++;
    end
    $display("-----------------------------------------------------------------");
  end    
endmodule

Simulator Output

-----------------------------------------------------------------
Value of a=0
Value of a=1
Value of a=2
Value of a=3
Value of a=4
-----------------------------------------------------------------

Click to execute on

while loop example 2

module while_loop;
  int a;
  initial begin
    $display("-----------------------------------------------------------------");

    while(a>5)
      begin
        $display("\tValue of a=%0d",a);
        a++;
      end
    $display("-----------------------------------------------------------------");
  end     
endmodule

Simulator Output

-----------------------------------------------------------------
-----------------------------------------------------------------

Click to execute on   

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