Placement_Logic_Code.c

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

#define MAX_STUDENTS 100
#define NAME_LEN     50
#define REGNO_LEN    15
#define PHONE_LEN    15

typedef struct {
    char  name[NAME_LEN];
    char  regno[REGNO_LEN];
    float per10;
    float per12;
    float cgpa;
    int   tier;        
    int   eligible;    
} Student;

Student students[MAX_STUDENTS];
int     student_count = 0;

void get_line(const char *prompt, char *buf, int len) {
    printf("%s", prompt);
    if (fgets(buf, len, stdin)) {
        size_t l = strlen(buf);
        if (l && buf[l-1] == '\n') buf[l-1] = '\0';
    }
}

int valid_regno(const char *r) {
    if (strlen(r) != 10) return 0;
    for (int i = 0; i < 2; i++) if (!isdigit(r[i])) return 0;
    for (int i = 2; i < 5; i++) if (!isalpha(r[i])) return 0;
    for (int i = 5; i < 10; i++) if (!isdigit(r[i])) return 0;
    return 1;
}

void classify_student(Student *s) {
    if (s->cgpa > 9.0 && s->per10 > 90.0 && s->per12 > 90.0) {
        s->tier = 1;
        s->eligible = 1;
    }
    else if (s->cgpa > 8.0 && s->per10 > 80.0 && s->per12 > 80.0) {
        s->tier = 2;
        s->eligible = 1;
    }
    else if (s->cgpa > 7.0 && s->per10 > 70.0 && s->per12 > 70.0) {
        s->tier = 3;
        s->eligible = 1;
    }
    else {
        s->tier = 4;
        s->eligible = 0;
    }
}

//Reclassification to show the Added or the edited details
void classify_all() {
    for (int i = 0; i < student_count; i++)
        classify_student(&students[i]);
}

// print one student
void print_student(const Student *s, int idx) {
    printf("%2d. %-15s | %-10s | 10th: %.2f%% | 12th: %.2f%% | CGPA: %.2f | Tier: %d | %s\n",
           idx+1, s->name, s->regno, s->per10, s->per12, s->cgpa, s->tier,
           s->eligible ? "Eligible" : "Ineligible");
}

// show all students
void show_students() {
    if (student_count == 0) {
        printf("No students to display.\n");
        return;
    }
    puts("\nCurrent Students:");
    for (int i = 0; i < student_count; i++)
        print_student(&students[i], i);
    puts("");
}

// Adding of the student
void add_student() {
    if (student_count >= MAX_STUDENTS) {
        printf("Max students reached (%d).\n", MAX_STUDENTS);
        return;
    }
    Student tmp;
    get_line("Enter name: ", tmp.name, NAME_LEN);

    do {
        get_line("Enter regno : ", tmp.regno, REGNO_LEN);
        if (!valid_regno(tmp.regno))
            printf("Invalid format. Try again.\n");
    } while (!valid_regno(tmp.regno));

    printf("Enter 10th %%: ");
    if (scanf("%f", &tmp.per10)!=1) tmp.per10=0;
    printf("Enter 12th %%: ");
    if (scanf("%f", &tmp.per12)!=1) tmp.per12=0;
    printf("Enter final CGPA: ");
    if (scanf("%f", &tmp.cgpa)!=1) tmp.cgpa=0;
    while(getchar()!='\n');  

    classify_student(&tmp);
    students[student_count++] = tmp;
    printf("Student added (now %d students).\n\n", student_count);
}


int find_by_regno(const char *r) {
    for (int i = 0; i < student_count; i++)
        if (strcmp(students[i].regno, r) == 0)
            return i;
    return -1;
}

// modification of the details
void modify_student() {
    char r[REGNO_LEN];
    get_line("Enter regno of student to modify: ", r, REGNO_LEN);
    int idx = find_by_regno(r);
    if (idx < 0) {
        printf("Not found.\n");
        return;
    }
    Student *s = &students[idx];
    printf("Modifying %s (%s)\n", s->name, s->regno);

    get_line(" New name (blank to keep): ", r, REGNO_LEN);
    if (r[0]) strncpy(s->name, r, NAME_LEN);

    get_line(" New 10th %% (blank to keep): ", r, REGNO_LEN);
    if (r[0]) s->per10 = atof(r);

    get_line(" New 12th %% (blank to keep): ", r, REGNO_LEN);
    if (r[0]) s->per12 = atof(r);

    get_line(" New CGPA (blank to keep): ", r, REGNO_LEN);
    if (r[0]) s->cgpa = atof(r);

    classify_student(s);
    printf("Student updated.\n");
}

// remove student
void remove_student() {
    char r[REGNO_LEN];
    get_line("Enter regno of student to remove: ", r, REGNO_LEN);
    int idx = find_by_regno(r);
    if (idx < 0) {
        printf("Not found.\n");
        return;
    }
    
    for (int i = idx; i < student_count - 1; i++)
        students[i] = students[i+1];
    student_count--;
    printf("Student removed.\n");
}

// Changing the eligiblity
void toggle_eligibility() {
    char r[REGNO_LEN];
    get_line("Enter regno to toggle eligibility: ", r, REGNO_LEN);
    int idx = find_by_regno(r);
    if (idx < 0) {
        printf("Not found.\n");
        return;
    }
    students[idx].eligible = !students[idx].eligible;
    printf("Now %s is %s for placement.\n",
           students[idx].name,
           students[idx].eligible ? "eligible" : "ineligible");
}

int main() {
    // login
    char user[20], pass[20];
    printf("                                                  Placement Cell                             \n");
    printf("Username: ");
    if (!fgets(user, sizeof user, stdin)) return 0;
    user[strcspn(user, "\n")] = 0;
    printf("Password: ");
    if (!fgets(pass, sizeof pass, stdin)) return 0;
    pass[strcspn(pass, "\n")] = 0;

    if (strcmp(user, "pcell") || strcmp(pass, "pcell")) {
        printf("Login failed.\n");
        return 0;
    }

    // Prefill 7 Avengers
    Student defaults[] = {
        {"Tony Stark",       "23BCY10001", 95.0, 93.0, 9.5, 0, 0},
        {"Steve Rogers",     "23BAI10002", 85.0, 88.0, 8.4, 0, 0},
        {"Bruce Banner",     "23BCE10003", 72.5, 75.0, 7.5, 0, 0},
        {"Natasha Romanoff", "23MEI10004", 68.0, 70.0, 6.8, 0, 0},
        {"Clint Barton",     "23BCY10005", 91.0, 89.0, 8.2, 0, 0},
        {"Peter Parker",     "23BAI10006", 92.0, 92.0, 9.0, 0, 0},
        {"Wanda Maximoff",   "23BCE10007", 98.0, 97.0, 9.6, 0, 0}
    };
    for (int i = 0; i < 7; i++) {
        classify_student(&defaults[i]);
        students[student_count++] = defaults[i];
    }

    // main menu
    int choice;
    do {
        printf("\nMenu:\n"
               " 1. Show all students\n"
               " 2. Add student\n"
               " 3. Modify student\n"
               " 4. Remove student\n"
               " 5. Toggle eligibility\n"
               " 0. Exit\n"
               "Enter choice: ");
        if (scanf("%d", &choice) != 1) choice = -1;
        while (getchar() != '\n');  // clear

        switch (choice) {
            case 1: show_students(); break;
            case 2: add_student();   break;
            case 3: modify_student();break;
            case 4: remove_student();break;
            case 5: toggle_eligibility(); break;
            case 0: printf("Goodbye.\n \xE2\x84\xA2 Snehil Shourya"); break;
            default: printf("Invalid choice.\n");
        }
    } while (choice != 0);

    return 0;
}