input

#include<allegro.h>
#include<stdio.h>
#include<string.h>
#define Helix "HELIX"
#define press "Press Any Key"
#define space "\t \t \t"
void read_string(char *str_to, int size);
char ch;
int main(void)
{
    if (allegro_init() != 0)
        return 1;
    install_keyboard();
    install_timer();
    if (set_gfx_mode(GFX_AUTODETECT, 320, 200, 0, 0) != 0)
    {
        if (set_gfx_mode(GFX_SAFE, 320, 200, 0, 0) != 0)
        {
            set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
            allegro_message("Unable to set any graphic mode\n%s\n", allegro_error);
            return 1;
        }
    }
    char users[100];
    //set_palette(desktop_palette);
    clear_to_color(screen, makecol(255, 255, 0));
    char start[100]="WELCOME";//we can use this also
    acquire_screen();
    textout_centre_ex(screen, font, start, SCREEN_W/2, SCREEN_H/4, makecol(0,0,255),-1);
    textout_centre_ex(screen, font, " TO ", SCREEN_W/2, SCREEN_H/3, makecol(0,255,0), -1);
    textout_centre_ex(screen, font, Helix, SCREEN_W/2, SCREEN_H/2, makecol(255,0,0), -1);
    textout_centre_ex(screen, font, press, SCREEN_W/2, SCREEN_H/1.5, makecol(255,0,0), -1);
    release_screen();
    readkey();
    Main_page(users);
    return 0;
}
END_OF_MAIN()
void Main_page(char *users)
{
Main_sec:
    while(1)
    {
        fflush(stdin);
        set_gfx_mode(GFX_AUTODETECT_FULLSCREEN,320,200,0,0);
        acquire_screen();
        clear_to_color(screen, makecol(0, 0, 0));
        textout_centre_ex(screen,font, Helix, SCREEN_W/2, SCREEN_H/5, makecol(0,0,255),-1);
        textout_centre_ex(screen,font, "1)lOGIN", SCREEN_W/2, SCREEN_H/3, makecol(0,0,255),-1);
        textout_centre_ex(screen,font, "2)SIGNUP", SCREEN_W/2, SCREEN_H/2, makecol(0,0,255),-1);
        textout_centre_ex(screen,font, "3)EXIT", SCREEN_W/2, SCREEN_H/1.5, makecol(0,0,255),-1);
        release_screen();
        ch=readkey();
        if((ch==49 )||(ch ==50)||(ch==51))
        {
            break;
        }
        else
        {
            textout_centre_ex(screen,font, "Please Enter valid Data", SCREEN_W/2, SCREEN_H/1, makecol(0,0,255),-1);
        }
    }
    if(ch==50)
    {
        Signup_page(users);
        goto Main_sec;
    }
    else if(ch==49)
    {
        login_page(users);
        goto Main_sec;
    }
    else
    {
    }
}
END_OF_FUNCTION(Main_page);
void Signup_page(char *users)
{
    set_gfx_mode(GFX_AUTODETECT_FULLSCREEN,320,200,0,0);
    acquire_screen();
    clear_to_color(screen, makecol(255, 255, 255));
    textout_centre_ex(screen,font, "SIGNUP", SCREEN_W/2, SCREEN_H/5, makecol(0,0,255),-1);
    textout_centre_ex(screen,font, "    NAME:", SCREEN_W/4, SCREEN_H/3, makecol(0,0,255),-1);
    textout_centre_ex(screen,font, "PASSWORD:", SCREEN_W/4, SCREEN_H/2, makecol(0,0,255),-1);
    release_screen();
    ch=readkey();

}
void login_page(char *users)
{
    char my_str[40],*poin;
    char name[100]="NAME:";
    char pass[100]="PASSWORD:";
    set_gfx_mode(GFX_AUTODETECT_FULLSCREEN,320,200,0,0);
    acquire_screen();
    clear_to_color(screen, makecol(255, 255, 255));
    textout_centre_ex(screen,font, "LOGIN", SCREEN_W/2, SCREEN_H/5, makecol(0,0,255),-1);
    textout_centre_ex(screen,font, name, SCREEN_W/4, SCREEN_H/3, makecol(0,0,255),-1);
    char my[40];
    read_string(my,40);
    textout_centre_ex(screen,font, pass, SCREEN_W/2, SCREEN_H/5, makecol(0,0,255),-1);
    char var[40];
    read_string(var,40);
    release_screen();
}
void read_string(char *str_to, int size) {
       int cur_pos = 0; // position of caret
       int the_key = 0;
       int i;
       for (i = 0; i < size; i++)
               str_to[i] = '\0'; // 'clean' the string

       while (the_key>>8 != KEY_ENTER)
       {
               the_key = readkey();
               if ((the_key & 0xff) >= ' ') // get only valid chars
               {
                       str_to[cur_pos] = the_key & 0xff;
                       cur_pos++;
                       if (cur_pos > size-2) cur_pos = size-2;
               }
               if (the_key >> 8 == KEY_BACKSPACE)
               {
                       str_to[cur_pos] = '\0'; // chop the string
                       cur_pos --;
                       if (cur_pos < 0) cur_pos = 0;
               }
               // lame redraw (use double buffer, whatever)
               clear(screen);
               textout(screen,font, str_to, 0,0, makecol(255,255,255));
       }
}