Linked list c++

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

using namespace std;

struct exam {
    char examName[40];
    char examCode[5];
    int date;
    int timeExam;
    int room;
    struct exam *next;
}*head, *tail, *curr;

void display(){
    int j=0;
    printf("------------------- Jadwal Ujian ----------------\n");
    for(j = 0; j < 6; j++) 
    printf("=");
    printf("\n");
    printf("| %-15s | %-20s | %-15s | %-8s | %-4s |\n",  "Kode", "Nama Matkul", "Tanggal", "Jam", "Ruangan");    
    for(j =0; j < 6; j++)
    printf("=");
    printf("\n");
    curr = head;
    while(curr) {
        printf("| %-15s | %-20s | %-15d | %-8d | %-4d |\n", curr->examCode, curr->examName, curr->date, curr->timeExam, curr->room);
        curr = curr->next; 
    }
    for(j=0; j<6; j++)
    printf("=");
    printf("\n");
    getchar();
    fflush(stdin);
}

void push(char examCode[], char examName[], int date, int timeExam, int room) {
    curr = (struct exam*)malloc(sizeof(struct exam));
    strcpy(curr->examCode, examCode);
    strcpy(curr->examName, examName);
    curr->date = date;
    curr->timeExam = timeExam;
    curr->room = room;
    if (head==NULL) {
        head = tail = curr;
    }else{
        tail->next = curr;
        tail = curr;
    }
    tail->next = NULL;
}

void pop(char examCode[]){
    curr = head;
    while(curr != NULL && strcmp(curr->examCode, examCode) != 0) {                        
        curr = curr->next;
    }
    if(curr == NULL){
        printf("Kode ujian tidak ditemukan\n");
    }else if(head==curr){
        head = head->next;
        free(curr);
        printf("Jadwal ujian berhasil dihapus\n");
    }else if(head!=curr && tail!=curr){
        struct exam * temp;
        temp = head;
        while(temp->next != curr) temp = temp->next;
        temp->next = curr->next;
        free(curr);
        printf("Jadwal ujian berhasil dihapus\n");
    }else if(tail==curr){
        exam *current=new exam;
        exam *previous=new exam;
        current=head;
        while(current->next!=NULL) {
            previous=current;
            current=current->next;
        }
        tail=previous;
        previous->next=NULL;
        free(current);
        printf("Jadwal ujian berhasil dihapus\n");
    }
}

void popall(){
    while(head!=NULL){
        curr=head;
        head=head->next;
        free(curr);
    }
}

void menu(){
    printf("\n Jadwal Ujian");
    printf("\n =============");
    printf("\n 1. Lihat Jadwal");
    printf("\n 2. Tambah Jadwal");
    printf("\n 3. Hapus Jadwal");
    printf("\n 4. Keluar");
    printf("\n >> Silakan pilih salah satu menu: ");
}

void clear(){
    for(int i=0; i<3; i++)
        printf("\n");
}

int main() {
   int choice;
    char examCode[5];
    char examName[40];
    int date;
    int timeExam;
    int room;
    do{
        clear();
        menu();
        scanf("%d", &choice);
        fflush(stdin);
        switch(choice) {
            case 1 : display();
                break;
            case 2 : 
               printf("Masukan Kode Ujian[5]: ");
               scanf("%s", examCode);
               if (strlen(examCode)>5){
                   printf("maksimal panjang kode adalah 5");
                   break;
               }
               fflush(stdin);
               printf("\n");
               getchar();
               printf("Masukan Nama Mata Kuliah[40]: ");
               scanf("%[^\n]s",examName);
                if (strlen(examName)>40){
                   printf("maksimal nama matkul adalah 40");
                   break;
               }
               fflush(stdin);
               printf("\n");
               getchar();
               printf("Masukan Tanggal [1...30]: ");
               scanf("%d", &date);
               if (date == 0 || date > 31) {
                   printf("maksimal tanggal adalah 31");
                   break;
               }
               fflush(stdin); 
               printf("\n");
               getchar();
               printf("Masukan Waktu Ujian [8...17]: ");
               scanf("%d", &timeExam);
               if (timeExam < 8 || timeExam > 17){
                   printf("waktu jam ujian adalah jam 8 sampai 17");
                   break;
               }
               fflush(stdin); 
               printf("\n");
               getchar();
               printf("Masukan Ruang Ujian [3]: ");
               scanf("%d", &room);
               fflush(stdin);
               push(examCode, examName, date, timeExam, room);
               getchar();
               fflush(stdin);
               break;
            case 3 :
                if(head==NULL){
                    printf("Tidak ada jadwal ujian..");
                }else{
                  
                    printf("Masukan Kode Ujian[5]: ");
                    scanf("%s", examCode);
                    fflush(stdin);
                    pop(examCode);
                }
                getchar();
                fflush(stdin);
                break;
            case 4 :
                popall();
                break;
        }
    }while(choice!=4);
}