File Manipulation in C

[SoreComet]

Hi Guys,

I was trying to code in C for the following.

You are given with 2 files, file1.txt and file2.txt. The contents of the file contain INTERGER values. Add the contents of the file and write them to another file file3.txt.

My code is as follows

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

int main()
{
    static int data,data1,sum;

    FILE *f1,*f2,*f3;
    f1 = fopen("C:\\file1.txt","r");
    f2 = fopen("C:\\file2.txt","r");
    f3 = fopen("C:\\file3.txt","w");

    while(( fscanf(f1,"%d",&data) != EOF ) || ( fscanf(f2,"%d",&data1) != EOF ))
    {
        if(data == EOF && data1 == EOF)
        {
            break;
        }
        else if(data == EOF)
        {
            sum += data1;
        }
        else if(data1 == EOF)
        {
            sum += data;
        }
        else
        {
            sum = sum + data + data1;
        }
    }

    fprintf(f3,"%d\n",sum);

    fclose(f1);
    fclose(f2);
    fclose(f3);

    return 0;
}

Contents of File1 --> 123
Contents of File2 --> 456

But after execution, when I open File3, it has the results as

702

Please help me with the code

P.S : I tried to add the contents without the while loop (i.e)., it can be applied for only one Input on each file and it worked fine. But I want to add the contents of the file that has multiple numbers in it.

Please help me

[sepp2k]

You seem to think that if the end of file is reached, fscanf will store EOF in the given variable. It won't - it will simply keep the variable unchanged. The only way to tell whether fscanf successfully read a value is to check the return value of fscanf - you can't tell by looking at the variable.

The easiest way to make your code work would be to simply have two loops after each other: One that goes through the first file and one that goes through the second. To avoid code duplication, you should define a function that takes a file as an argument and then sums that file. Then you can simply call that function once with the first file as the argument and once with the second.

[rishif2]

replace while(( fscanf(f1,"%d",&data) != EOF ) || ( fscanf(f2,"%d",&data1) != EOF ))

to while(( fscanf(f1,"%d",&data) != EOF ) && ( fscanf(f2,"%d",&data1) != EOF ))

hope this helps you . . .

[sepp2k]

That won't actually fix the issue and it will cause another issue: The loop will now quit as soon as one of the files' end has been reached, so if the files contain a different number of entries, it won't read all the numbers.

[rishif2]

I know that
if both file will not at EOF then code will work otherwise seperate code will have to write

[SoreComet]

@sepp2k Thanks a TON man! I finally got my code working

Here is my code

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

int getfromfile(FILE **fp)
{
    int data = 0;
    int sum = 0;
    while(fscanf(*fp,"%d",&data) != EOF)
    {
        sum += data;
    }
    return sum;
}

int main()
{
    int data = 0;
    int data1 = 0;

    FILE *f1,*f2,*f3;
    f1 = fopen("C:\\file1.txt","r");
    f2 = fopen("C:\\file2.txt","r");
    f3 = fopen("C:\\file3.txt","w");

    data = getfromfile(&f1);
    data1 = getfromfile(&f2);

    fprintf(f3,"%d",(data+data1));

    fclose(f3);
    fclose(f2);
    fclose(f1);

    return 0;
}