## FOR For Loop

Section: Flow Control

### Usage

The `for` loop executes a set of statements with an index variable looping through each element in a vector. The syntax of a `for` loop is one of the following:

      for (variable=expression)
         statements
      end

Alternately, the parenthesis can be eliminated

      for variable=expression
         statements
      end

or alternately, the index variable can be pre-initialized with the vector of values it is going to take:

      for variable
         statements
      end

The third form is essentially equivalent to `for variable=variable`, where `variable` is both the index variable and the set of values over which the for loop executes. See the examples section for an example of this form of the `for` loop.

### Examples

Here we write `for` loops to add all the integers from `1` to `100`. We will use all three forms of the `for` statement.

    --> accum = 0;
    --> for (i=1:100); accum = accum + i; end
    --> accum

    ans =
     5050

The second form is functionally the same, without the extra parenthesis

    --> accum = 0;
    --> for i=1:100; accum = accum + i; end
    --> accum

    ans =
     5050

In the third example, we pre-initialize the loop variable with the values it is to take