@* A Simple CWEB Document. This is a simple CWEB document that
incorporates documentation and code for a short C program that prints
square roots of real numbers. Running `./sqrt 25.0' at the shell will
print 5.

@c
@<Header files@>@/
@<Program@>@/

@ The standard headers are included to start with,

@<Header ...@>=
#include <stdio.h>
#include <stdlib.h>

@* The Program. Here is the program to find the square root of a number.

@<Program@>=
int main(int argc, char* argv[])
{
    if (argc < 2)
    {
        printf("Usage: sqrt <n>\n");
        exit(1);
    }
    printf("%15s %15s\n", "NUMBER", "SQUARE ROOT");
    for (; argc > 1; --argc)
    {
        double n = atof(argv[argc - 1]);
        printf("%15.4f %15.4f\n", n, sqrt(n));
    }
    return 0;
}

@ Now that we have used the |sqrt()| function, we need to include the
appropriate header file.

@<Header ...@>=
#include <math.h>