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!

I have updated the content "A<B, B<C, C<A (Like rock scissors game, rock<cloth, cloth< scissor, scissor<rock)"

Answer 1

#include <stdio.h>
#include <string.h>
#include<time.h> 
 
 
struct account {
        char username[50];
        char password[50];
        int history[50][5];
        int games;
};
 
void printHistory(struct account accounts[], int id) {
        printf("\nPlayer %s history\n", accounts[id].username);
        printf("Total Games played: %d\n\n", accounts[id].games);
        if (accounts[id].games > 0) {
                printf("%5s %20s %20s %20s %20s %20s\n", "Game", "Rounds", "Player wins", "Computer wins", "Draws", "overall Result");
                for (int i = 0; i < accounts[id].games; i++) {
                        printf("%5d %20d %20d %20d %20d %20s\n", i + 1, accounts[id].history[i][0], accounts[id].history[i][1],
                                accounts[id].history[i][2], accounts[id].history[i][3], (accounts[id].history[i][4] == -1 ? "Computer wins" : accounts[id].history[i][4] == 0 ? "Draw" : "You Win"));
                }
                printf("\n");
        }
        else
                printf("Play atleast one game to generate history!\n\n");
}
 
//returns the number of accounts read
int readAccountsFile(char filename[], struct account accounts[]) {
        FILE *infile;
        struct account read;
        infile = fopen(filename, "r");
        if (infile == NULL)
        {
                return 0;
        }
 
        int count = 0;
        while (fread(&accounts[count], sizeof(struct account), 1, infile)) {
                count++;
        }
 
        fclose(infile);
 
        return count;
}
 
int writeAccountsFile(char filename[], struct account accounts[], int count) {
        FILE *outfile;
        outfile = fopen(filename, "w");
        if (outfile == NULL)
        {
                fprintf(stderr, "\nError opening file\n");
                exit(1);
        }
 
        for (int i = 0; i < count; i++) {
                fwrite(&accounts[i], sizeof(struct account), 1, outfile);
        }
 
 
        if (fwrite != 0){}      
        else
                printf("error writing file !\n");
        fclose(outfile);
}
 
 
//returns accounts array index of registered user if login sucessfull else -1
int login(struct account accounts[], int n) {
        char username[50], password[50];
        printf("Enter Username: ");
        gets(username);
        printf("Enter Password: ");
        gets(password);
 
 
        for (int i = 0; i < n; i++) {
                if (strcmp(accounts[i].username, username) == 0  && strcmp(accounts[i].password, password) == 0) {
                        return i;
                }
        }
        return -1;
}
 
//returns total number of accounts after registering or -1 if registration failed
int registerUser(struct account accounts[], int n) {
        char username[50], password[50];
        printf("Enter Username: ");
        gets(username);
        printf("Enter Password: ");
        gets(password);
 
 
        for (int i = 0; i < n; i++) {
                if (strcmp(accounts[i].username, username) == 0 ){
                        printf("username exists\n");
                        return -1;
                }
        }
 
 
        //initialize array
 
        for (int j = 0; j < 50; j++) {
                for (int k = 0; k < 5; k++) {
                        accounts[n].history[j][k] = 0;
                }
        }
        
 
 
        strcpy(accounts[n].username, username);
        strcpy(accounts[n].password, password);
        accounts[n].games = 0;
        return n + 1;
        
}
 
void game(struct account accounts[], int id) {
        char choice;
        int c=0;
        srand(time(0));
        
        while (1)
        {
                //clear input buffer
                while ((c = getchar()) != '\n' && c != EOF) {}
                printf("A, B or C? :");
                choice = getchar();
                choice = toupper(choice);
                int ichoice = choice - 'A';
                //input validation
                if (ichoice > 2 || ichoice < 0) {
                        printf("Enter A, B or C only!:\n");
                        continue;
                }
 
                int comp = rand() % 3;
 
                printf("Computer choose %c and you choose %c\n",'A' + comp, choice);
 
 
                if (ichoice == comp) {
                        accounts[id].history[accounts[id].games][3]++;
                        printf("Draw\n");
                }
                else if (ichoice == 0 && comp == 2) {
                        //player win
                        accounts[id].history[accounts[id].games][1]++;
                        printf("You win\n");
                }
                else if (ichoice == 2 && comp == 1) {
                        //player win
                        accounts[id].history[accounts[id].games][1]++;
                        printf("You win\n");
                }
                else if (ichoice == 1 && comp == 0) {
                        //player win
                        accounts[id].history[accounts[id].games][1]++;
                        printf("You win\n");
                }
                else {
                        //computer wins
                        accounts[id].history[accounts[id].games][2]++;
                        printf("Computer wins\n");
                }
 
 
                //increment no. of games
                accounts[id].history[accounts[id].games][0]++;
 
                //update stats
                if (accounts[id].history[accounts[id].games][2] > accounts[id].history[accounts[id].games][1]) {
                        accounts[id].history[accounts[id].games][4] = -1;
                }
                else if (accounts[id].history[accounts[id].games][1] > accounts[id].history[accounts[id].games][2]) {
                        accounts[id].history[accounts[id].games][4] = 1;
                }
                else {
                        accounts[id].history[accounts[id].games][4] = 0;
                }
 
 
                printf("-1 to quit, anything else to continue: ");
                scanf("%d", &c);
                if (c == -1) {
                        accounts[id].games++;
                        printf("Game ended\n");
                        break;
                }
                
        }
}
 
 
 
int main() {
        //array for storing all the accounts in the datafile
        struct account accounts[50];
 
 
        int choice = 0, loggedin = -1, ntemp;
        char c;
        //call function to read accounts from data file into accounts array and return the number
        //of accounts read
        int n = readAccountsFile("accounts.txt", accounts);
        //login or register loop
        while (1)
        {
                printf("1. Login\n2. Register\n");
                scanf("%d", &choice);
                //clear input buffer
                while ((c = getchar()) != '\n' && c != EOF) {}
 
                
                switch (choice)
                {
                case 1:
                        loggedin = login(accounts, n);
                        break;
 
                case 2: 
                        ntemp = registerUser(accounts, n);
                        if (ntemp >=0) {
                                n = ntemp;
                                loggedin = n - 1;
                                //write data file after every registration of account
                                writeAccountsFile("accounts.txt", accounts, n);
                        }
                        break;
 
 
                default:
                        continue;
                }
 
                if (loggedin >= 0) {
                        printf("Logged in sucessfully! \n");
                        break;
                }
                else {
                        printf("Log in failed! \n");
                }
        }
 
 
        //menu after login or register
        while (1)
        {
                printf("1. Start new game\n2. Review game history\n3. Clear game history\n4. Logout\n");
                scanf("%d", &choice);
 
                switch (choice)
                {
                case 1:
                        game(accounts, loggedin);
                        //write data file after every game
                        writeAccountsFile("accounts.txt", accounts, n);
                        break;
 
                case 2:
                        printHistory(accounts,loggedin);                        
                        break;
 
                case 3:
                        //clear history
                        accounts[loggedin].games = 0;
                        printf("Your game history has been cleared.\n");
                        //write to data file after clearing history
                        writeAccountsFile("accounts.txt", accounts, n);
                        break;
                case 4:
                        return 0;
                        break;
 
                default:
                        break;
                }
 
        }
 
        return 0;
}

Output