Project: Student Database

Time for a real project. We will build a student registry, using everything we have learned: structs, pointers, dynamic memory, arrays and string functions

The program manages a list of students. Each student has a name and a grade. We will

1. Create students dynamically with malloc
2. Store them in an array of pointers
3. Print all students
4. Find the student with the highest grade
5. Free the memory

Here is the struct we will use

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

typedef struct {
    char name[50];
    int grade;
} Student;

int main(void) {
    Student s = {"Ritchie", 95};
    printf("%s: %d\n", s.name, s.grade);
    return 0;
}

And here is how we create a student dynamically

Student *create_student(const char *name, int grade) {
    Student *s = malloc(sizeof(Student));
    strncpy(s->name, name, sizeof(s->name) - 1);
    s->name[sizeof(s->name) - 1] = '\0';
    s->grade = grade;
    return s;
}

The function allocates memory on the heap, fills in the fields and returns a pointer. The caller becomes responsible for freeing that memory later

To print all students

void print_all(Student *students[], int n) {
    for (int i = 0; i < n; i++) {
        printf("%s: %d\n", students[i]->name, students[i]->grade);
    }
}

Notice students[i]->name: each element of the array is a pointer to a Student, so we use -> instead of .

To find the top student

Student *find_top(Student *students[], int n) {
    Student *top = students[0];
    for (int i = 1; i < n; i++) {
        if (students[i]->grade > top->grade) {
            top = students[i];
        }
    }
    return top;
}

Mission: The computer lab registry

It's 1974. You are the shift operator at the university's computer lab. Students finishing the programming exam come to your teletype and dictate their name and grade. You enter them into the registry, one student at a time

Write a program that

1. Reads an integer n: the number of students
2. Reads, n times, a name and a grade (integer), and creates a student with create_student, storing the pointer in an array
3. Calls print_all to print each student as "Name: Grade"
4. Calls find_top and prints "Top student: Name (Grade)"
5. Frees all allocated memory, with free, before finishing

Example

Input

4
Ritchie 95
Thompson 82
Kernighan 98
McIlroy 76

Output

Ritchie: 95
Thompson: 82
Kernighan: 98
McIlroy: 76
Top student: Kernighan (98)

Example

Input

2
Ana 88
Mihai 91

Output

Ana: 88
Mihai: 91
Top student: Mihai (91)