main.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// structure
struct LoginCredentials {
    char username[50];
    char password[50];
};

struct Student {
  char name[50];
  int age;
  char major[50];
  float percentage;
  int attendance;
};

// functions declaration
void calculatePERC(struct Student *student);
float percentage(float total, float fM);
void inputAttendance(struct Student *student);
void executeUserLogin();

// main function
int main() {
  executeUserLogin();
  
  struct Student students[100];
  FILE *fptr;
  int choice, num_students = 0, num_saved_stds = 1;

  do {
    printf("------------------------------------------------");
    printf("\n*********************Menu***********************\n");
    printf("------------------------------------------------\n");
    printf("1. Add Student\n");
    printf("2. Calculate Percentage\n");
    printf("3. Input Attendance\n");
    printf("4. View Recent Students\n");
    printf("5. View Saved Students\n");
    printf("6. Save Recent Info\n");
    printf("7. Exit\n");
    printf("------------------------------------------------\n");
    printf("Enter your choice: ");
    scanf("%d", &choice);
    getchar();
    system("clear");
    switch (choice) {
    case 1:
      printf("\n------------------------------------------------");
      printf("\n****************Student Form********************\n");
      printf("------------------------------------------------\n");
      printf("Enter name: ");
      fgets(students[num_students].name, 50, stdin);
      printf("Enter age: ");
      scanf("%d", &students[num_students].age);
      getchar(); // Consume the newline character left by scanf
      printf("Enter major: ");
      fgets(students[num_students].major, 50, stdin);
      // getchar();
      students[num_students].percentage = 0;
      students[num_students].attendance = 0;
      num_students++;
      system("clear");
      printf("\nStudent Added Successfully!!\n");
      printf("\n");
      break;

    case 2:

      if (num_students > 0) {
        int student_index;
        printf("\n------------------------------------------------\n");
        printf("Enter student index (0 to %d): ", num_students - 1);
        scanf("%d", &student_index);
        if (student_index >= 0 && student_index < num_students) {
          calculatePERC(&students[student_index]);
          system("clear");
          printf("\nPercentage calculated for %s\n",
                 students[student_index].name);
        } else {
          system("clear");
          printf("\n⚠ Invalid student index\n");
        }
      } else {
        system("clear");
        printf("\n⚠No students to calculate Percentage\n");
      }
      printf("\n");
      break;
    case 3:
      if (num_students > 0) {
        int student_index;
        printf("\n------------------------------------------------\n");
        printf("Enter student index (0 to %d): ", num_students - 1);
        scanf("%d", &student_index);
        if (student_index >= 0 && student_index < num_students) {
          inputAttendance(&students[student_index]);
          system("clear");
          printf("Attendance recorded for %s!!!\n",
                 students[student_index].name);
        } else {
          system("clear");
          printf("\n⚠Invalid student index\n");
        }
      } else {
        system("clear");
        printf("\n⚠No students to record attendance\n");
      }
      printf("\n");
      break;

    case 4:
      if (num_students > 0) {
        printf("\nRecently added Students:\n");
        for (int i = 0; i < num_students; i++) {
          printf("-----------------------\n");
          printf("Name: %s", students[i].name);
          printf("Age: %d\n", students[i].age);
          printf("Major: %s", students[i].major);
          printf("Percentage: %.2f%\n", students[i].percentage);
          printf("Attendance: %d/30\n", students[i].attendance);
          printf("-----------------------\n");
          printf("You should save it permanently!!\n");
        }
      } else {
        printf("\n⚠No students to display\n");
      }
      break;

    case 5:
      if (num_saved_stds > 0) {
        fptr = fopen("stdsData.txt", "r");
        char ch;
        ch = fgetc(fptr);

        while (ch != EOF) {
          printf("%c", ch);
          ch = fgetc(fptr);
        }
        fclose(fptr);
      } else {
        printf("\n⚠No students to display\n");
      }
      break;

    case 6:
      if (num_students > 0) {
        fptr = fopen("stdsData.txt", "a");
        for (int i = 0; i < num_students; i++) {
          fprintf(fptr, "-----------------------\n");
          fprintf(fptr, "Name: %s", students[i].name);
          fprintf(fptr, "Age: %d\n", students[i].age);
          fprintf(fptr, "Major: %s", students[i].major);
          fprintf(fptr, "Percentage: %.2f%\n", students[i].percentage);
          fprintf(fptr, "Attendance: %d/30\n", students[i].attendance);
          fprintf(fptr, "-----------------------\n");
          num_saved_stds++;
        }
        fclose(fptr);
        printf("\nData Successfully saved \n");
      } else {
        printf("\n⚠No students to save!!\n");
      }
      break;
    case 7:
      system("clear");
      printf("\nExiting program......\n");
      break;
    default:
      printf("\n⚠Invalid choice, please try again\n");
    }
  } while (choice != 7);
  printf("\n");
  return 0;
}

// Functions defination
void executeUserLogin() {
    int option1;

    while(1) {
        printf("SIGN UP (1) or LOGIN (2)?\n");
        scanf("%d", &option1);

        if (option1 == 1) {
            ///////////////////SIGN UP//////////////////////
            struct LoginCredentials user;
            FILE *file = fopen("login.txt", "r");

            if (file == NULL) {
                file = fopen("login.txt", "w");
                printf("Enter a username: ");
                scanf("%s", user.username);
                printf("Enter a password: ");
                scanf("%s", user.password);

                fprintf(file, "%s\t%s", user.username, user.password);
                printf("Sign up successful!\n");
                fclose(file);
              break;
            } else {
                printf("YOU HAVE ALREADY SIGNED UP!!! \n");
                fclose(file);
            }
            /////////////////opt1 end

        } else if (option1 == 2) {
            //////////////////////////LOGIN///////////////////////
            char userInputUsername[50];
            char userInputPassword[50];

            printf("Enter your username: ");
            scanf("%s", userInputUsername);
            printf("Enter your password: ");
            scanf("%s", userInputPassword);

            FILE *fptr;
            fptr = fopen("login.txt", "r");
            if (fptr != NULL) {
                char username[50];
                char password[50];
                fscanf(fptr, "%s\t%s", username, password);

                if (strcmp(userInputUsername, username) == 0 && strcmp(userInputPassword, password) == 0) {
                    printf("LOGIN SUCCESSFUL!\n");
                    fclose(fptr);
                  break;
                    
                } else {
                    printf("Invalid username or password!\n");
                    fclose(fptr);
                }
            } else {
                printf("Error opening file\n");
            }
            ////////////////////////LOGIN END//////////////////////
        } else {
            continue; // exit while loop if neither 1 nor 2 is entered
        }
    }
}


void calculatePERC(struct Student *student) {

  float phy, che, mat, nep, eng, comp, fM, percent;

  printf("\nEnter full marks : ");
  scanf("%f", &fM);
  printf("\nEnter physics marks : ");
  scanf("%f", &phy);
  printf("\nEnter chemistry marks : ");
  scanf("%f", &che);
  printf("\nEnter math marks : ");
  scanf("%f", &mat);
  printf("\nEnter nepali marks : ");
  scanf("%f", &nep);
  printf("\nEnter english marks : ");
  scanf("%f", &eng);
  printf("\nEnter computer marks : ");
  scanf("%f", &comp);
  float total = phy + che + mat + nep + eng + comp;

  percent = percentage(total, fM);

  student->percentage = percent;
}

void inputAttendance(struct Student *student) {
  int att;
  printf("\nEnter this month attendence:");
  scanf("%d", &att);
  student->attendance = att;
}

float percentage(float total, float fM) { return (total / (fM * 6)) * 100; }