#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
struct Student {
    int roll;
    char name[50];
    float marks;
};
 
// Function Prototypes
void addStudent();
void viewStudents();
void searchStudent();
void updateStudent();
void deleteStudent();
 
int main() {
    int choice;
 
    do {
        printf("\n===== Student Record Management System =====\n");
        printf("1. Add Student Record\n");
        printf("2. View All Students\n");
        printf("3. Search Student by Roll Number\n");
        printf("4. Update Student Record\n");
        printf("5. Delete Student Record\n");
        printf("6. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
 
        switch(choice) {
            case 1: addStudent(); break;
            case 2: viewStudents(); break;
            case 3: searchStudent(); break;
            case 4: updateStudent(); break;
            case 5: deleteStudent(); break;
            case 6: printf("Exiting program...\n"); break;
            default: printf("Invalid choice! Try again.\n");
        }
    } while(choice != 6);
 
    return 0;
}
 
// Function to Add a Student
void addStudent() {
    FILE *file = fopen("students.txt", "a");
    struct Student s;
 
    if(file == NULL) {
        printf("Error opening file!\n");
        return;
    }
 
    printf("Enter Roll Number: ");
    scanf("%d", &s.roll);
    printf("Enter Name: ");
    scanf("%s", s.name);
    printf("Enter Marks: ");
    scanf("%f", &s.marks);
 
    fprintf(file, "%d %s %.2f\n", s.roll, s.name, s.marks);
    fclose(file);
 
    printf("Student record added successfully!\n");
}
 
// Function to View All Students
void viewStudents() {
    FILE *file = fopen("students.txt", "r");
    struct Student s;
 
    if(file == NULL) {
        printf("No records found!\n");
        return;
    }
 
    printf("\n--- Student Records ---\n");
    printf("Roll\tName\t\tMarks\n");
    printf("----------------------------------\n");
 
    while(fscanf(file, "%d %s %f", &s.roll, s.name, &s.marks) != EOF) {
        printf("%d\t%-10s\t%.2f\n", s.roll, s.name, s.marks);
    }
 
    fclose(file);
}
 
// Function to Search Student by Roll Number
void searchStudent() {
    FILE *file = fopen("students.txt", "r");
    struct Student s;
    int roll, found = 0;
 
    if(file == NULL) {
        printf("No records found!\n");
        return;
    }
 
    printf("Enter Roll Number to Search: ");
    scanf("%d", &roll);
 
    while(fscanf(file, "%d %s %f", &s.roll, s.name, &s.marks) != EOF) {
        if(s.roll == roll) {
            printf("Record Found:\n");
            printf("Roll: %d\nName: %s\nMarks: %.2f\n", s.roll, s.name, s.marks);
            found = 1;
            break;
        }
    }
 
    if(!found)
        printf("No record found for Roll No: %d\n", roll);
 
    fclose(file);
}
 
// Function to Update Student Record
void updateStudent() {
    FILE *file = fopen("students.txt", "r");
    FILE *temp = fopen("temp.txt", "w");
    struct Student s;
    int roll, found = 0;
 
    if(file == NULL) {
        printf("No records found!\n");
        return;
    }
 
    printf("Enter Roll Number to Update: ");
    scanf("%d", &roll);
 
    while(fscanf(file, "%d %s %f", &s.roll, s.name, &s.marks) != EOF) {
        if(s.roll == roll) {
            printf("Enter New Name: ");
            scanf("%s", s.name);
            printf("Enter New Marks: ");
            scanf("%f", &s.marks);
            found = 1;
        }
        fprintf(temp, "%d %s %.2f\n", s.roll, s.name, s.marks);
    }
 
    fclose(file);
    fclose(temp);
 
    remove("students.txt");
    rename("temp.txt", "students.txt");
 
    if(found)
        printf("Record updated successfully!\n");
    else
        printf("Record not found!\n");
}
 
// Function to Delete Student Record
void deleteStudent() {
    FILE *file = fopen("students.txt", "r");
    FILE *temp = fopen("temp.txt", "w");
    struct Student s;
    int roll, found = 0;
 
    if(file == NULL) {
        printf("No records found!\n");
        return;
    }
 
    printf("Enter Roll Number to Delete: ");
    scanf("%d", &roll);
 
    while(fscanf(file, "%d %s %f", &s.roll, s.name, &s.marks) != EOF) {
        if(s.roll != roll) {
            fprintf(temp, "%d %s %.2f\n", s.roll, s.name, s.marks);
        } else {
            found = 1;
        }
    }
 
    fclose(file);
    fclose(temp);
 
    remove("students.txt");
    rename("temp.txt", "students.txt");
 
    if(found)
        printf("Record deleted successfully!\n");
    else
        printf("Record not found!\n");
}