/* Write a program that accepts as parameters the names of the three files and copy their contents to a new file as follows:

One line first file
One line second file
One line from a third
2 lines of the first file
2 rows from a hand
2 rows from a third
.
.
.
i lines of the first file
i ranks second file
i rows from a third

If one short files from others - others continue to copies files. */


#include<stdio.h>
#include<stdlib.h>
#define N 1000
// main() must return an integer
int main(int argc, char *argv[]) //settings function main ()
{
	int i, j = 0;
	char content[N];
	FILE *file1=NULL, *file2=NULL, *file3=NULL, *copyFile=NULL;

	if (argc > 4) // cheking if a we have not  more 3 files
	{
		printf("Incompatible number of parameters!");
		return 1;
	}

     // open a file for write a new content from 3 another files
	copyFile = fopen("d:\\homework\\myfile.txt", "w");
	// opening 3 files to read a content and whose path is passed as an argument
	file1 = fopen("argv[1]", "r");  // can write the same example  file1 = fopen("d:\\homework\\myfile2.txt", "r")
	file2 = fopen("argv[2]", "r");  // can write the same example  file2 = fopen("d:\\homework\\myfile3.txt", "r")
	file3 = fopen("argv[3]", "r");  // can write the same example  file3 = fopen("d:\\homework\\myfile4.txt", "r")

	// copyFile returns NULL pointer on failure
	if (copyFile == NULL)
		printf("Can't create a file to store a data\n");
	// fopen returns NULL pointer on failure
	if ((file1 == NULL) || (file2 == NULL) || (file3 == NULL))
		printf("File can not be open\n");
	else
		// do the loop for reading the files from file1,file2 and file3 and wrting in to the copyFile
		while (!feof(file1) || !feof(file2) || !feof(file3))
		{
			for (i = 0; i < j + 1; i++) // loop for file1
			{
				if (fgets(content, sizeof(content), file1) != NULL)  // reading lines from a file
					puts(content); // output on display
				fprintf(copyFile, "%s\n", content);
			}
			for (i = 0; i < j + 1; i++) //loop for file2
			{
				if (fgets(content, sizeof(content), file2) != NULL)  // reading lines from a file
					puts(content); // output on display
				fprintf(copyFile, "%s\n", content);
			}
			for (i = 0; i < j + 1; i++)  // loop for file3
			{
				if (fgets(content, sizeof(content), file3) != NULL)  // reading lines from a file
					puts(content); // output on display
				fprintf(copyFile, "%s\n", content);
			}
			j++;
		}
	fclose(file1);  // file1 is the file pointer associated with file to be closed

	fclose(file2) ; // file2 is the file pointer associated with file to be closed

	fclose(file3);  // file3 is the file pointer associated with file to be closed

	fclose(copyFile); // copyFile is the file pointer associated with file to be closed

    return 0; // Zero indicates success, while any
  // Non-Zero value indicates a failure/error
}