CODEWITHSUNDEEP
ccommand-line-arguments
Anas
Anas

Reputation: 31

How to call a function in another C file with a subset of the command-line arguments?

How can I call this convert function using command line and from argument 2 onwards start converting the strings to int and store in an array?

#include <stdio.h>

int main (int argc , char* argv[])
{
    int i;
 
    if (argc < 2)

    {
        printf("Error: Less than two arguments\n");
    }
    else 
    {
        for(i=0; i<argc; i++)
        {
            printf("[%d] : %s\n", i , argv[i]); 
        }
    }
    return 0;
}

Function in the same directory but in a separate C file:

void convert ( char* parray[] ,int array[] )
{   
    int i;
 
    printf("The converted array = ");

    for (i=0; i< LENGTH; i++)
    {
        array[i] = atoi(parray[i]);

        printf(" %d" , array[i]);
    }
    printf("\n");
}

Upvotes: 0

Views: 251

Answers (2)

alex01011
alex01011

Reputation: 1702

Create a module, have the declarations in a separate file, and the implementations in a separate.

functions.h:

#ifndef FUNCTIONS_H /* include guard */
#define FUNCTIONS_H

void convert(char *parray[], int array[], int length);

#endif

functions.c:

#include "functions.h" /* include your header with the declarations */
#include <stdio.h>
#include <stdlib.h>

void convert(char *parray[], int array[], int length)
{

    int i;

    printf("The converted array = ");

    for (i = 0; i < length; i++)
    {
        array[i] = atoi(parray[i]);

        printf(" %d", array[i]);
    }
    printf("\n");

    return;
}

main.c:

#include "functions.h"
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    int i, *arr = NULL;

    if (argc < 2)
    {
        printf("Error: Less than two arguments\n");
    }
    else
    {
        arr = malloc((argc - 1) * sizeof(int)); /* array can be static too */

        if (arr == NULL)
        {
            exit(EXIT_FAILURE);
            /* handle error */
        }

        convert(&argv[1], arr, argc - 1);

        free(arr); /* free when you exit */
    }

    return 0;
}

Compilation:

clang -c functions.c && clang main.c functions.o

OR

clang functions.c main.c

Output:

$ ./a.out 15 20 -90 18 20 20 8 8 8 81
$ The converted array =  15 20 -90 18 20 20 8 8 8 81

Upvotes: 0

sekthor
sekthor

Reputation: 504

You can compile both files into the same executable, e.g like:

gcc -o main main.c convert.c

To use the function in convert.c in main.c, you will have to declare the function before you define the main() function, like this:

#include<stdio.h>

void convert ( char* parray[] ,int array[] );

int main (int argc , char* argv[])
{
    // your code ..

    //you may now use the convert function inside the main function
    convert(param1, param2);
}

Alternatively, you could create a header file for convert.c, called convert.h, like this:

#ifndef CONVERT_H
#define CONVERT_H

void convert ( char* parray[] ,int array[] );

#endif

Then, you could include the headerfile in the main file like this:

#include<stdio.h>
#include "convert.h"

int main (int argc , char* argv[])
{
    // use convert here somewhere
    convert(param1, param2);
}

Upvotes: 1

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