Any help please, I'm trying to convert this C++ code to C code, but I'm having problem with fflush() function

Question

Any help please, I'm trying to convert this C++ code to C code, but I'm having problem with fflush() function, or if there is another code functions like this, please do share it.

    #include <iostream.h>
    #include <time.h>
    #include<dos.h>
    int main()
    {
        cout << "Loading";
        cout.flush();
        for (int j=0; j<2; ++j) {
            for (int i = 0; i < 3; i++) {
                cout << ".";
                cout.flush();
                sleep(1);
            }
            cout << "\b\b\b   \b\b\b";
        }
    
        return 0;
    }
//________________________________________________________________________

    #include <stdio.h>>
    #include <unistd.h>
    int main()
    {
       printf("Loading");
        fflush();
        for (int j=0; j<2; ++j){
            for (int i = 0; i < 3; i++) {
                printf(".");
                fflush();
                sleep(1);
            }
           printf("\b\b\b   \b\b\b");
        }
        return 0;
    }

Answer 1

fflush takes an argument - the stream it is supposed to flush. You'd need to use fflush(stdout) .

Another problem is that the C++ code is semantically wrong too. Rather than using cout or printf to stdout , for such diagnostic messages one would be using cerr / stderr , which should be unbuffered anyway. using that you wouldn't probably need the fflush . Ie

#include <stdio.h>
#include <unistd.h>


int main(void)
{
    fprintf(stderr, "Loading");
    for (int j=0; j<2; ++j){
        for (int i = 0; i < 3; i++) {
            fprintf(stderr, ".");
            sleep(1);
        }
        fprintf(stderr, "\b\b\b   \b\b\b");
    }
}

Answer 2

fflush needs file pointer as argument. This would flush the local buffer data(stored in primary memory - mostly dram) corresponding to the file into the actual file stored in the secondary storage. For your case use fflush(stdout)