command line programming in c

There are methods to interact with a program in command line itself,by command line i mean the terminal by which the program can be executed.Is it possible to supply arguments to a program in the command line ?
YES !,


we first learn to compile and run a program using gcc

say you have a program hello.c


to compile we use                       gcc -c hello.c or a simple gcc hello.c would do


The above command creates a default object file by the name a.out so if you wanna execute the program you need to      ./a.out and hit enter

but if you want to give your name to the object file then you can do so by
gcc hello.c -o yourname
the program then can be run by  just  ./yourname





NOW FOR THE COMMAND LINE ARGUMENT PASSING

lets say you made a object file name by using   gcc prog.c -o name

now to pass arguments to this program prog from the command line ,The prog program would have


int main(int argc,char * argv[])
{   .......
    ........
    ........
}

int argc indicate how many arguments are passed and argv will store the arguments

that is if you want to pass a alist of arguments to your prog program with object name then


          ./name prog.c 25 wow! 56.78 this$is$a$string

now observe the syntax i wrote ./object (name of the program ie prog.c) (argument list)

the argument list is seperated by integers and the first is an integer .2nd a string ,3rd a float and the 4th is a string but i have used delimiters such as $ to indicate space..and its your job to replace the $ with space inside the program.
you could have used any other delimiter apart from $

now inside the program the argc is holding value 5

and argv[0] = "prog.c"
argv[1] = 25
argv[2] ="wow!"
and so on

Thats about it ,this provides a simple enough usage of command line argument passing