Dragon/Lessons/Control Structures

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Control Structures[edit]

In this chapter we are going to learn about the control structures provided by the Dragon programming language.

Branching[edit]

  • If Statement

Syntax:

	if(Expression)
        {
		Block of statements
          }
	else if(Expression)
         {
		Block of statements
          }
	else {
		Block of statements
           }

Example:

        select "types"
        select "graphic"
       
	nOption = int(prompt("1) Say Hello \n2) About")

	if nOption = 1	
        {
           name = prompt("Enter your name: ")
          showln "Hello " + name 
          }
	else if nOption = 2 
       {      
         showln "Sample : using if statement" 
          }
	else
         { 
        showln "bad option..."
	}


Looping[edit]

  • While Loop

Syntax:

	while(Expression)
          {
		Block of statements
          }


  • For Loop

Syntax:

	for (identifier=Initialize value, expression , expression [step expression])
        {

		Block of statements
	}

Example:

	// print numbers from 1 to 10
	for (x = 1,x<=10,x++)
        {
        showln x  
         }


  • Foreach Loop

Syntax:

	for (identifier : List/String)
		Block of statements
	}

Example:

	aList = [1,2,3,4]	//create list contains numbers from 1 to 10
	for( x in aList )
         {
           showln x   // print numbers from 1 to 10
          }

Do While Loop[edit]

Syntax:

	
	do {
             body
      } while condition

Example:

	x = 1 
	do {
		showln x 
		x++ 
             }
	while(x <= 10)