Illustrates how to read command-line arguments in C. Prints usage info if not provided with any argument.

args.c

/*
Illustrates how to get arguments from the command-line.

Usage:
    
    args 10.0

will print out the number you entered. If not given any 
argument, will print out usage info.
*/

#include <stdio.h>

int main(int argc, char *argv[]){
    float arg;

    if ( argc != 2 ) {
        printf( "usage: %s float \n", argv[0] );
    } 
    else {
        sscanf(argv[1], "%f", &arg); // reads command-line argument

        printf("Command-line argument: %f \n", arg);
    }

    return(0);
}