C Program To Copy One File To Another

C Program :
/* Aim: Write a program to accept two file names as command line arguments. Copy the contents of the first file to the second file such that the case of all alphabets is reversed. */ 

#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>

void main()
{
	FILE *fp1,*fp2;
	char ch,fname[100];

	printf("\n Enter the name of first file to open:- ");
	scanf("%s",fname);

	if(fp1==NULL)
	{
	printf("\n File does not exist \n \n");
	exit(0);
	}

	fp1=fopen("fname","r");

	printf("\n Enter the name of second file to open:- ");
	scanf("%s",fname);

	if(fp2==NULL)
	{
	printf("\n File does not exist \n \n");
	exit(0);
	}

	fp2=fopen("fname","w");

	while(!feof(fp1))
	{
	ch=fgetc(fp1);
	if(isalpha(ch))
	{
		if(isupper(ch))
		ch=tolower(ch);
		else
		ch=toupper(ch);
	}

	fputc(ch,fp2);
	}

	printf("\n All Content Copied. \n \n");
}

 

/* Output of above code:- 

[root@ugilinux ~]# cc e18a1.c
[root@ugilinux ~]# ./a.out

 Enter the name of first file to open:- a.txt

 Enter the name of second file to open:- b.txt

 All Content Copied. 

*/