Argument list in c

Question

what is an argument list in c? Please I need a very simple explanation that if possible I'll remember for life! also... show me one containing an array

Answer 1

Command line arguments are the values that follow the program name when you run a c program from a command line. Let's look at an example:

./myprogram red blue green

./myprogram is the program name. "red", "blue" and "green" are three arguments.

When a c program executes, all of the arguments are stored in a special array called argv[].

The special variable "argc" contains the number of elements in the argv array, including the program name.

Remember that arrays start with element 0. The argv[] array will contain the arguments based on their position, plus one special entry. argv[0] will always contain the program name as it was called.

So, in this example, the vars are as follows:

argc = 4
argv[0] = "./myprogram"
argv[1] = "red"
argv[2] = "blue"
argv[3] = "green"

Here's a simple program to demonstrate the contents:

#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{
    printf("argc = %i\n",argc);

    for (int i = 0; i < argc; i++ )
    {
        printf("argv[%i] = \"%s\"\n",i,argv[i]);
    }
}

So that's the explanation of argc, argv[] and command line arguments.

If you're talking about passing arguments to a function call, that's an entirely different topic that's taught a couple weeks into the class. ;-)

If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)