coingrab.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>  /* for time() */

int gen_random_num(int coins);
void print_welcome();
void print_coins(int coins, int i);


int main(){
 // Seed the RNG for computer randomized selections
    srand(time(NULL));
 
 // Initialization Block
    int coins                   =  30;  /* Total coins used in the game */
    int psel                    =   0;
    int csel                    =   0;
    int i                       =   0;

    print_welcome();

    while(coins > 0){
        //print the amount of coins
        print_coins(coins, i);

        //get player input
        printf("Please choose 1, 2, or 3: ");
        scanf("\n%d", &psel);
  
        //check that player input is within the bounds
        do{
            if(psel < 1){
                printf("You have to take at least one coin. ");
                scanf("\n%d", &psel);
            } else if(psel > 3 || psel > coins){
                printf("Dont take that many coins, greedy! ");
                scanf("\n%d", &psel);
            }
        }while(psel < 1 || psel > 3 || psel > coins);
  
        coins -= psel;
        if(coins == 0){
            printf("You took the last coin! You Win!\n");
            break;
        } else{
            printf("You take %d coins, there are %d coins left.\n", psel, coins);
        }  

        csel = gen_random_num(coins);
        coins -= csel;
        if(coins == 0){
            printf("The computer took the last coin. You lose.\n");
            break;
        } else{
            printf("The computer takes %d coins, there are %d coins left.\n", csel, coins);
        }
    }
    return 0;
}

// Prints the welcoming message for the game.
void print_welcome(){
    printf("Welcome to Coin Grabber.\n");
    printf("To play, take either 1, 2, or 3 coins from the stack,\n");
    printf("and the computer will make its selection. The one who takes\n");
    printf("the last coin from the stack wins. To start, press enter");
    getchar();
}

//Selects the computer's Choice between 1, 2, or 3
int gen_random_num(int coins){
    int r = (rand() % 3) + 1; //r will be either 1, 2, or 3
 
    // prevent the computer from taking more coins than there are left
    // or makes the CPU take the remaining coins if the remaining is
    // less than or equal to 3, to simulate a human decision. 
    if(r > coins){
        r = coins;
    } else if(coins <= 3){
        r = coins;
    }  
    return r;
}


//Prints the remaining coins in a decimal, and ascii format
void print_coins(int coins, int i){
    printf("\nRemaining coins (%d): ", coins);
    for(i = 0; i < coins; i++){
        printf("o");
    }
    printf("\n");
}