# Suppressing and controlling output

Matlab is frequently used with vectors and matrices containing hundreds
or thousands of entries. In such cases it is a great inconvenience to have
the answers written to the terminal. It is easy, however, to prevent
Matlab from writing the answer to any calculation: simply terminate a
statement by a semi-colon (`;`) and Matlab will execute it without
writing out the result. For example, generate a vector of 100 evenly
spaced points between 0 and π
(remember the semi-colon, and distinguish
it from the colons (`:`) which are used to define the vector
conveniently):

t = linspace(0, pi, 100);

Now you can examine the first 10 values, say, by typing `t(1:10)`
(without a semi-colon). If you just type `t` you will get all 100
points. We can also make a vector of the values of `sin(t)` for
`0<= t <= π`

sint = sin(t);

Did you remember the semi-colon?

In engineering we often need to use `scientific' notation, in which
numbers are written in the `mantissa `x`
exponent' form *x.xxxx* **x** *10 ^{x}*.
We can make Matlab
output results in this form. First let's look at the values in the vector

`sint`near to

`t=π/2`say the 49th, 50th, 51st and 52nd entries:

sint(49:52)

Now switch to scientific notation by typing

format short e

and look at those values again. You will see the values to 4 decimal places, with powers of 10 (labelled `e' for exponent). If you would like to see the values to the full accuracy with which they are stored in Matlab, type

format long e

and look at them again. If you would like to restore the original format, type

format

on its own.