The if Block.
The while loop.
The for loops.
The switch/case block.
The next/continue statement.
The break statement.

The If Block

The if block is of the usual form

     if(condition1)
	statements1
     else if(condition2)
	statements2
     else if(icondition3)
	statements3
     .
     .
     .
     .
     else
	statements3
     end

Here condition1, condition2, etc. are boolean valued expressions and statements1, statements2 etc. are groups of statements.

The While Loop

The while block is of the usual form

     while(condition)
	statements
     end

Here condition is a boolean valued expression and statements is a group of statements.

The For Loops

A few different forms of the for block are allowed. The usual Matlab style block is of the form

     for varname=first:inc:last
	statements
     end

     for varname=first:last
	statements
     end

in which inc is assumed to be 1. In these forms of the for block, the group of statements specified by statements is executed as many times as necessary for the value of the variable varname to range from first thru last with its value incremented in each execution by the specified inc. Depending upon the value of first and inc, the last execution of the block may or may not correspond the value of varname being last.

The C/Java style of the for block of the form

     for(init;cond;eblock) 
	statements
     end

can also be used. It is equivalent to

     init;
     while(cond)
	statements
        eblock; 
     end

Finally, it is also possible to use the Java for block for collections. It is of the form

     for(varname:array)
	statements
     end

where, obviously, array is any array. This style is equivalent to

     m=numel(array)
     for i=1:m
	varname=array[i];
	statements
     end

The Switch-Case Block

The switch-case block is of the usual form

     switch expression
  	case value1:
		statements1
  	case value2:
		statements2
  	case value3:
		statements3
	.
	.
	.
	default:
		defaults
     end

which is equivalent to

	temp=expression
  	if temp==value1
		statements1
  	else if temp==value2
		statements2
  	else if temp==value3
		statements3
	.
	.
	.
  	else 
		defaults
	end

where temp is any valid variable name.

The next Statement

The next, or, equivalently, continue statement is used to prematurely jump to the beginning of a for or a while loop, typically if some condition is satisfied. Generally, its usage is of the form

     while(condition)
	statements1
	if(condition)
	  next
	end
	statements2
     end

     for varname=first:inc:last
	statements1
	if(condition)
	  next
	end
	statements2
     end

Clearly, if the condition is satisfied in any of the loops shown above, statements following the next statement are not executed, and the execution jumps to the beginning of the loop. Note that next can be used in any of the various forms of the for loop.

The break Statement

The break statement is used to prematurely terminate a for or a while loop, typically if some condition is satisfied. Generally, its usage is of the form

     while(condition)
	statements1
	if(condition)
	  break
	end
	statements2
     end

     for varname=first:inc:last
	statements1
	if(condition)
	  break
	end
	statements2
     end

Clearly, if the condition is satisfied in any of the loops shown above, the loops are prematurely terminated and the thread of execution jumps to the first statement immediately following the end of the loop. Note that break can be used in any of the various forms of the for loop.