#include <stdio.h>
#include <conio.h>
#include <dos.h>

long free_disk(int driver);

void main(){
    int driver = 0;
    long int spc;

    spc = free_disk(driver);
    printf("\n free space is : %ld", spc);
    getch();
}

long free_disk(int driver){
    union REGS in, out;
    in.h.ah = 0x36;
    in.h.dl = driver;
    intdos(&in, &out);
    return((long) out.x.ax * (long) out.x.bx * (long) out.x.cx);
}

#include <stdio.h>
#include <Windows.h>

long long free_disk_space(const char *driver){
    ULARGE_INTEGER freebytes;
    if(GetDiskFreeSpaceExA(
        driver,
        &freebytes,
        NULL,
        NULL)){
            return freebytes.QuadPart;
        }
    return -1;
}


int main(){
    long long space = free_disk_space("c:\\");
    if(space != -1){
        printf("\n\tFree Space is : %lld bytes\n", space);
    }else{
        printf("\n\tError reading disk space !\n");
    }


    return 0;
}

#include <stdio.h>
#include <windows.h>

int main(){
    for (int i = 0; i < 3;i++){
        Sleep(2500);
        printf("ok\n");
    }
}