coursework.c

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <time.h>
#include <string.h>
#include <math.h>

typedef struct {
  char id[7];
  int score;
  int time;
} Entry;
typedef struct {
  int first;
  char oper;
  int second;
  int result;
} Equation;
// this function is used to judge if the ID is legal
// this function accept a char array parameter which store the inputed ID
// return 1 if the form is legal, otherwise return 0
int validation(char id[]) {
  int flag = 1;
  if (!isalpha(id[0]) || !isalpha(id[1])) flag = 0;
  for (int i = 2; i != 6; i++)
    if (!isdigit(id[i])) flag = 0;
  if (id[6] != '\0') flag = 0;
  return flag;
}
// randomly generate 10 equations to an Equation array
// the generating process contain the following steps:
// 1. randomly generate a number from 0 to 3, which matches to one of the operators
// 2. if the operator is +/*, generate the augend/multiplier and the addend/multiplicand
//    if the operator is -//,generate the result and the subtrahend/divisor
// 3. calculate the result if the operator is +/*
//    calculate the minuend/dividend if the operator is-//
// 4. if any part of the equation is larger that 99, randomly generate the numbers again
void generate(Equation e[]) {
  srand((unsigned)time(NULL));
  for (int i = 0; i != 10; i++) {
    int seed = rand() % 4;
    switch (seed) {
    case 0: {
      e[i].oper = '+';
      e[i].first = rand() % 100;
      e[i].second = rand() % (100 - e[i].first);
      e[i].result = e[i].first + e[i].second;
      break;
    }
    case 1: {
      e[i].oper = '-';
      e[i].result = rand() % 100;
      e[i].second = rand() % (100 - e[i].result);
      e[i].first = e[i].result + e[i].second;
      break;
    }
    case 2: {
      e[i].oper = '*';
      e[i].first = rand() % 100;
      if (e[i].first == 0) e[i].second = rand() % 100;
      else e[i].second = rand() % (99 / e[i].first + 1);
      e[i].result = e[i].first * e[i].second;
      break;
    }
    case 3: {
      e[i].oper = '/';
      e[i].result = rand() % 100;
      if (e[i].result == 0) e[i].second = rand() % 99 + 1;
      else e[i].second = rand() % (99 / e[i].result) + 1;
      e[i].first = e[i].result * e[i].second;
      break;
    }
    }
  }
}
// this function is used to run the main test part
// the function accept an user Entry as a parameter
// the function operate according to the following sequence:
void exam(Entry *user) {
  user->score = 0;
  time_t begin, end;
  Equation e[10];
  int input[10];
  generate(e);
  begin = time(NULL);
  for (int i = 0; i != 10; i++) {
    printf("%d %c %d = ", e[i].first, e[i].oper, e[i].second);
    scanf("%d", &input[i]);
    if (input[i] == e[i].result) user->score += 10;
  }
  end = time(NULL);
  user->time = end - begin;
  printf("Prob.\t| Correct Answ.\t| Ur Answ\n");
  for (int j = 0; j != 10; j++)
    printf("%d %c %d\t| %d\t\t| %d\n", e[j].first, e[j].oper, e[j].second, e[j].result, input[j]);
  printf("Your score is: %d\n", user->score);
}

// this function is used to check the history score of current user
// this function accept two parameters
// the first is a file pointer, another one is a char array which contain the current user ID
// the file that the function reads need to be exist and in correct form
void check(FILE *c, char id[]) {
  c = fopen("record.txt", "r");
  Entry read;
  while(fscanf(c, "%s%d%d", read.id, &read.score, &read.time) != EOF) {
    if (strcmp(read.id, id) == 0)
      printf("%s\t%d\t%d seconds\n", read.id, read.score, read.time);
  }
  fclose(c);
}

int main() {
  // declare two file pointer
  // f for file output, and c for file input
  FILE *f, *c;
  Entry user;
  do {
    printf("Please input your four digit ID no:");
    scanf("%s", user.id);
    if (validation(user.id) == 0) printf("Invalid ID\n");
  } while(validation(user.id) == 0);
  char choice;
  do {
    // TODO
    /* if 'enter' is not declared, the enter that user inputed will be
       filled in 'choice', which means that the loop need to be ran for
       another time before it can accept user input.*/
    char enter;
    scanf("%c", &enter);
    printf("Enter the number of choice to continue:\n");
    printf("1. Start a test\n");
    printf("2. Check scores\n");
    printf("3. Exit\n");
    scanf("%c", &choice);
    switch (choice) {
    case '1': {
      f = fopen("record.txt", "a+");
      exam(&user);
      fprintf(f, "%s\t", user.id);
      fprintf(f, "%d\t", user.score);
      fprintf(f, "%d\n", user.time);
      fclose(f);
      break;
    }
    case '2': {
      check(c, user.id);
      break;
    }
    case '3': {
      break;
    }
    default: {
      printf("Invalid input\n");
      break;
    }
    }
  } while (choice != '3');
  return 0;
}