Thread: Reading from file and writing to a different file

When I try to copy one file over to another file, character by character, a new output file is created but nothing copied over. Does anyone know what I am doing wrong?

Code:

fopen_s(&filein, argv[i], "rb");    //open source file
        sourceLength = strlen(argv[i]) + 1;    
        strcpy_s(sourceFilename, 100, argv[i]);    


//Manipulate source filename by removing the extension
for (int i = sourceLength; i >= 0; i--)    //starting from 
        {
            if (sourceFilename[i] == '.')
            {
                sourceFilename[i] = 0;    //append null byte 
                break;
            }
        }


        strcat_s(sourceFilename, 100, ".bak");    //concatenate 

        fopen_s(&fileout, sourceFilename, "wb");    //open output

        if (fileout == NULL)
        {
            printf("Cannot open target file.");    //output error 
            fclose(fileout);
            exit(1);
        }


        while (ch != EOF)
        {
            ch = getchar();    //read character from source file

            if (ch == EOF)
            {
               break;    //break out of while loop if EOF is 
            }
           else
            {
                putchar(ch);    //wirte character from source file 
            }
}

I think one of the problems here is that you are reading the characters from the default input channel in c. Read about these fucntions:

C library function - fputc()
C library function - getc()
C library function - getchar()


Also take a look at this examples it's very similar to what you want to achieve
C library function fopen()
I have not tested it because I do not have the whole program but perhaps these changes will point in the right direction

Code:

while (ch != EOF) {
    ch = getc(filein);    //read character from source file
    fputc(ch, fileout);    //wirte character from source file 
}

Sweet! You were right, fredlo. Thanks so much!

You are welcome