Rock_Paper_Scissor_Game3.cpp

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define rounds 4 //pre-defining the total number of rounds for the game
static int userScore = 0;
static int computerScore = 0;
static int machine;
static char user;
char properInput()//returns only the first character given input as the choice
 {
   char c=getchar();
   if(c>='A'&&c<='Z')c = c - 'A' + 'a';//converting the uppercase into lowercase
   while(getchar()!='\n');//ignoring all other characters given input till the user presses enter
   return c;
 }
char computerChoice()//returns a random choice for the computer for every round
 {
   srand(time(0));//this ensures that random numbers are generated according to the given time, hence providing variety every time
   machine = rand()%3;//this ensures that there are only three possible values: 0,1 and 2
  if(machine==0)return 'r';
  else if(machine==1)return 'p';
  else return 's';
 }
void userChoice()//takes input the choice of the user for every round
 {
  printf("\nInput your choice: ");
  user=properInput();
  while(user!='r' && user!= 'p' && user!='s'){
    printf("Invalid choice, re-input your choice: ");
    user=properInput();
  }
 }
void printRules()//prints the rules of the game
 {
  printf("Rock can beat scissors, paper can beat rock and scissors can beat paper");
  printf("\nInput r for rock, the p for paper and s for scissors");
 }
void game(int currentRound)//recursive function to execute the game for the pre-defined number of rounds
 {
  if(currentRound==rounds)return;//base case which allows complete exit from the function
  userChoice();
  char computer = computerChoice();
  if(computer=='r')printf("Machine played rock. ");
  else if(computer=='p')printf("Machine played paper. ");
  else printf("Machine played scissors. ");
  if(user==computer)
  {
    printf("The round is a draw.\n");
  }
  else if(user=='r' && computer=='s' || user=='p' && computer=='r' || user=='s' && computer=='p')
  {
    printf("You win this round.\n");
    userScore++;
  }
  else
  {
    printf("You lose this round.\n");
    computerScore++;
  }
  game(++currentRound);//starting the next round
 }
void result()//prints the outcome of all the rounds
{
  printf("You scored %d and the system scored %d, ",userScore,computerScore);
  if(userScore==computerScore)printf("it is a draw.\n");
  else if(userScore>computerScore)printf("you win.\n");
  else printf("you lose.\n");
}
int main()//calls the required functions to execute the program
{
  printf("There will be %d round(s).\n",rounds);
  printRules();
  game(0);
  result();
  return 0;
}