Question

Good evening, here is a C program question.

I wanna to write a very small game. The rule of the game is like rock scissors. Both of the player and the computer generate a letter taking the value A, B, C. And A<B, B<C, C<A (Like rock scissors game, rock<cloth, cloth< scissor, scissor<rock)

Requirement 1: New users need to register an account with a username and password. Actually, the account should be a structure type variable containing: a username, a password and a record of the game history (The game history should be stored in a two-dimensional array and containing the following: Number of rounds in a game; Number of player wins; Number of computer wins; Number of draws; Whether or not the game was overall a win draw of loss). All of the accounts should be stored in a data file and accessed by the program.

Requirement 2: When the user have successfully registered or log on to an already registered account, the program should have the following choices: a) Start a new game; Review their game history; Clear their game history; log out.

And please write in C and avoid using global pointers. Thank you!

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
// ROCK SCISSOR GAME WITH FILE AND STRUCTURE
struct account
{
char username[20],password[20];
int history[50][4];
};

int randno(int n)
{
   int rand_max = RAND_MAX - (RAND_MAX % n);
   int ret;
   while ((ret = rand()) >= rand_max);
   return ret/(rand_max / n);
}

int wrandno(int *tbl, int len)
{
   int i, sum, r;
   for (i = 0, sum = 0; i < len; sum += tbl[i++]);
   if (!sum) return randno(len);

   r = randno(sum) + 1;
   for (i = 0; i < len && (r -= tbl[i]) > 0; i++);
   return i;
}

int main()
{
   char uname[20], password[20],un[20],pwd[20];
   struct account acc;
   char umove[10], cmove[10], line[255];
   int user, comp;
   int tbl[]={0,0,0};
   int tbllen=3;
   int choice,n,i,j,nrounds,cwins,pwins,gdraws,n1,n2,n3,n4;
   FILE *fp,*fptemp;
   clrscr();
  
   printf("\n***** Welcome to Rock-Cloth-Scissors *****\n");
   printf("\n1. Already Registered User");
   printf("\n2. New User");
   printf("\nEnter your type : ");
   scanf("%d", &n);
   if (n == 1)
   {
       fp = fopen("users.txt","r");
       printf("Username : ");
       scanf("%s", uname);
       printf("Password : ");
       scanf("%s", password);
       if (fp == NULL)
       {
           printf("Error reading the details!!");
           exit(1);
       }
       while (fp)
       {
           fscanf(fp, "%s %s %d %d %d %d ", un, pwd, &nrounds, &cwins,&pwins,&gdraws);
           if (strcmp(uname, un) == 0 && strcmp(password, pwd) == 0)
           {
               printf("Successfully logged in.");
               strcpy(acc.username, uname);
               strcpy(acc.password, password);
               acc.history[0][0] = nrounds;
               acc.history[0][1] = cwins;
               acc.history[0][2] = pwins;
               acc.history[0][3] = gdraws;
              
               break;
           }
       }
       fclose(fp);
   }
   else if (n == 2)
   {
       fp = fopen("users.txt", "a");
       printf("Username : ");
       scanf("%s", uname);
       printf("Password : ");
       scanf("%s", password);
       if (fp == NULL)
       {
           printf("Error reading the details!!");
           exit(1);
       }
       nrounds = cwins = pwins = gdraws = 0;
       fprintf(fp, "%s %s %d %d %d %d ", uname, password, &nrounds, &cwins, &pwins, &gdraws);
          
       printf("Account created successfully.");
       strcpy(acc.username, uname);
       strcpy(acc.password, password);
       acc.history[0][0] = nrounds;
       acc.history[0][1] = cwins;
       acc.history[0][2] = pwins;
       acc.history[0][3] = gdraws;      
       fclose(fp);
   }
   choice = 0;
   while (choice != 4)
   {
       printf("\n\n Welcome to the Game");
       printf("\n1. Start a new game");
       printf("\n2. Review game history");
       printf("\n3. Clear History");
       printf("\n4. Logout");
       scanf("%d", &choice);
       switch (choice)
       {
       case 1:
           mainloop:
           while (1)
           {
               printf("\n\nPlease press 1 for Rock, 2 For Cloth, 3 for Scissors, 4 to Quit\n");
               srand(time(NULL));
               comp = (wrandno(tbl, tbllen) + 1) % 3;
               scanf("%d",&user);
               if ((user > 4) || (user < 1))
               {
                   printf("Please enter a valid number!\n");
                   continue;
               }
               switch (comp)
               {
               case 1:
                   strcpy(cmove, "Rock");
                   break;
               case 2:
                   strcpy(cmove, "Cloth");
                   break;
               case 3:
                   strcpy(cmove, "Scissors");
                   break;
               default:
                   printf("\nComputer Error, set comp=1\n");
                   comp = 1;
                   strcpy(cmove, "Rock");
                   break;
               }
               switch (user)
               {
               case 1:
                   strcpy(umove, "Rock");
                   break;
               case 2:
                   strcpy(umove, "Cloth");
                   break;
               case 3:
                   strcpy(umove, "Scissors");
                   break;
               case 4:
                   break;                  
               default:
                   printf("\nError! Enter number between 1 to 4.");
                   goto mainloop;
               }
               if (user == 4)
                   break;
               if ((user + 1) % 3 == comp)
               {
                   nrounds++;
                   cwins++;
                   printf("\nComp Played: %s\nYou Played: %s\nSorry, You Lost!\n", cmove, umove);
               }
               else if (comp == user)
               {
                   nrounds++;
                   gdraws++;
                   printf("\nComp Played: %s\nYou Played: %s\nDraw!! :p\n", cmove, umove);
               }
               else
               {
                   nrounds++;
                   pwins++;
                   printf("\nComp Played: %s\nYou Played: %s\nYou Won!!!\n", cmove, umove);
               }
               acc.history[0][0] = nrounds;
               acc.history[0][1] = cwins;
               acc.history[0][2] = pwins;
               acc.history[0][3] = gdraws;
               tbl[user - 1]++;
           }
           break;
       case 2:
           printf("\n\nYOUR GAME HISTORY");
           printf("\nNo of rounds played : %d", nrounds);
           printf("\nYour score : %d", pwins);
           printf("\nComputer's score : %d", cwins);
           printf("\nNo of draws : %d", gdraws);
           if (pwins > cwins)
               printf("\nCongrats!! You are the WINNER!!!");
           else
               printf("\nComputer wins!!!");
           break;
       case 3:
           nrounds = cwins = pwins = gdraws = 0;
           acc.history[0][0] = nrounds;
           acc.history[0][1] = cwins;
           acc.history[0][2] = pwins;
           acc.history[0][3] = gdraws;
           printf("\nHISTORY CLEARED.");
           break;
       case 4:
           fp = fopen("users.txt", "r");
           fptemp = fopen("tmp.txt", "w");
           while (!feof(fp))
           {
               fscanf(fp, "%s %s %d %d %d %d", un, pwd, &n1, &n2, &n3, &n4);

               if (strcmp(uname, un) == 0)
               {
                   fprintf(fptemp, "%s %s %d %d %d %d\n", uname, password, nrounds, cwins, pwins, gdraws);
               }
               else
               {
                   fprintf(fptemp, "%s %s %d %d %d %d\n", un, pwd, n1, n2, n3, n4);
               }
           }
           fclose(fp);
           fclose(fptemp);
           remove("users.txt");
           rename("tmp.txt", "users.txt");
           printf("Goodbye! Thanks for playing!\n");
           return 0;
       }
   }

  
}