Question

#include <stdio.h>
#include <string.h>
#include <cstdlib>

const int KEY=118;

int main()
{
    FILE* hOFile = fopen("file1","w");
    FILE* hIFile;
    char sign;

    for(int i=254; i>=0; i--)
    fprintf(hOFile,"%c",i);

    fclose(hOFile);

    hIFile = fopen("file1","r");
    hOFile = fopen("file2","w");

    for(int i=254; i>=0; i--)
    {   
        fscanf(hIFile,"%c",&sign);
        fprintf(hOFile,"%c",(sign^KEY));
    }

    fclose(hIFile);
    fclose(hOFile);

    hIFile=fopen("file2","r");
    hOFile=fopen("file3","w");

    for(int i=254; i>=0; i--)
    {
        fscanf(hIFile,"%c",&sign);
        fprintf(hOFile,"%c",(sign^KEY));
    }

    fclose(hIFile);
    fclose(hOFile);
}

I meant that file3 to be identical with file1. Unfortunately, file3 crashes after ASCII KEY-9 character.To be specific, for this example:

File1:

ţýüűúůř÷öőôóňńđďîíěëęéčçćĺäăâáŕßŢÝÜŰÚŮŘ×ÖŐÔÓŇŃĐĎÎÍĚËĘÉČÇĆĹÄĂÂÁŔżľ˝Ľ»şą¸·¶µ´ł˛±°Ż®­¬«Ş©¨§¦Ą¤Ł˘ˇ źžťś›š™—–•”“’‘ŹŽŤŚ‹Š‰‡†…„‚€~}|{zyxwvutsrqponmlkjihgfedcba`_^][ZYXWVUTSRQPONMLKJIHGFEDCBA@?>=<;:9876543210/.-,+*)(‘&%$#”!

File3:

ţýüűúůř÷öőôóňńđďîíěëęéčçćĺäăâáŕßŢÝÜŰÚŮŘ×ÖŐÔÓŇŃĐĎÎÍĚËĘÉČÇĆĹÄĂÂÁŔżľ˝Ľ»şą¸·¶µ´ł˛±°Ż®­¬«Ş©¨§¦Ą¤Ł˘ˇ źžťś›š™—–•”“’‘ŹŽŤŚ‹Š‰‡†…„‚€~}|{zyxwvutsrqponmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

Answer 1

You have to open the files in read-binary mode (rb, not r) and write-binary mode (wb, not just w), or the system will try to do some conversions for you which you don’t want.