Editing C syntax (section)

===Command-line arguments===
The [[parameter]]s given on a [[command line]] are passed to a C program with two predefined variables - the count of the command-line arguments in {{code|argc}} and the individual [[Parameter|arguments]] as [[character string]]s in the pointer array {{code|argv}}. So the command:

 myFilt p1 p2 p3

results in something like:
{|class="wikitable" style="font-family: monospace,monospace;"
|-
|m||y||F||i||l||t||style="background:#CCC;"|\0||p||1||style="background:#CCC;"|\0||p||2||style="background:#CCC;"|\0||p||3||style="background:#CCC;"|\0
|-
|colspan="7" align="center"|argv[0]||colspan="3" align="center"|argv[1]||colspan="3" align="center"|argv[2]||colspan="3" align="center"|argv[3]
|}

While individual strings are arrays of contiguous characters, there is no guarantee that the strings are stored as a contiguous group.

The name of the program, {{code|argv[0]}}, may be useful when printing diagnostic messages or for making one binary serve multiple purposes. The individual values of the parameters may be accessed with {{code|argv[1]}}, {{code|argv[2]}}, and {{code|argv[3]}}, as shown in the following program:

<syntaxhighlight lang=C>
#include <stdio.h>

int main(int argc, char *argv[])
{
    printf("argc\t= %d\n", argc);
    for (int i = 0; i < argc; i++)
        printf("argv[%i]\t= %s\n", i, argv[i]);
}
</syntaxhighlight>