`main()`

was.
Here we will take a much more detailed tour through functions.
Consider the program:
#include <stdio.h> #include <math.h> float pythag( float side_a, float side_b ) ; float square( float x ) ; main() { float adjacent, opposite, hypotenuse ; printf( "What lengths are the adjacent and opposite sides? " ) ; scanf( "%f%f", &adjacent, &opposite ) ; hypotenuse = pythag( adjacent, opposite ) ; printf( "The lenght of the hypotenuse is %f\n", hypotenuse ) ; } float pythag( float side_a, float side_b ) { return( sqrt( square( side_a ) + square( side_b ))) ; } float square( float x ) { return( x * x ) ; }(We've left out the comments as we will do in most of the examples in this tutorial.)

Looking at the functions for `pythag()`

and
`square()`

at the bottom
of the program, we see that they look a lot like the function
declarations for main that we've already seen, but with some
additional features.
(Ignore the `pythag`

and `square`

at the
beginning of the program for now.
We'll see what that's for in Part 2-5.)
In particular they specify *parameters* and *return types.*
The function:

float square( float x ) { return( x * x ) ; }can be read as the C translation of the English sentence:

The floating point square of a floating point number, x, is given by x * x.The first

`float`

, as in `float square(...`

,
specifies that the function
square will return a floating point number as its result.
The `float x`

inside the parentheses specified that
`square`

will take one `x`

inside the function.
If the function takes more than one parameter, then we list them
separated by commas as in the definition of `pythag()`

.
Give the first line of a function definition (up to but not including
the opening brace ({)) for a function called `conv`

that takes an integer argument (call it `x`

) and produces
a character as output.
(Remember Part 1-4 lists some of the common
data types in C.)