Sorting and Searching with linked list

#include <iostream>
#include <stdlib.h>

using namespace std;

struct data{
    string nama;
    int npm;
};

struct node{
    int index;
    data data;
    node *next;
};

node *baru,*awal=NULL,*akhir=NULL,*bantu,*bantu2;

int indeks=-1;

void buatNode(string thisNama,int thisNpm){
    indeks++;
    baru = new node;
    baru->next = NULL;
    baru->index = indeks;
    baru->data.nama = thisNama;
    baru->data.npm = thisNpm;
    if(awal==NULL){
        awal=akhir=baru;
    }else{
        akhir->next = baru;
        akhir=baru;
    }
}

void tambahData(){
    string thisNama;
    int thisNpm;
    cout << "Masukkan nama :";
    cin >> thisNama;
    cout << "Masukkan npm :";
    cin >> thisNpm;
    buatNode(thisNama,thisNpm);
}

void view(){
    if(indeks!=-1){
        cout << "Data : " << endl;
        cout << "No. \tNPM \t-> \tNAMA \t-> \tINDEX NODE" << endl;
        bantu = awal;
        for(int i=0;i<=indeks;i++){
            cout << i+1 << ". \t" << bantu->data.npm << "\t-> \t" << bantu->data.nama << "\t-> \t" << bantu->index << endl;
            bantu=bantu->next;
        }
    }
}

void urutkanMenaik(){
    node *tmp;
    bantu = awal;
    for(int i=0;i<indeks;i++){
        bantu=bantu2=awal;
        while(bantu->next!=NULL){
            if(bantu->data.npm>bantu->next->data.npm){
                tmp = bantu->next;
                bantu->next = bantu->next->next;
                tmp->next = bantu;
                if(bantu==awal){
                    awal=bantu2=tmp;
                }else{
                    bantu2->next=tmp;
                }
                bantu=tmp;
            }
            bantu2 = bantu;
            bantu = bantu->next;
        }
    }
}

void acak(){
    node *tmp;
    bantu = awal;
    for(int i=0;i<indeks;i++){
        bantu=bantu2=awal;
        while(bantu->next!=NULL){
            tmp = bantu->next;
            bantu->next = bantu->next->next;
            tmp->next = bantu;
            if(bantu==awal){
                awal=bantu2=tmp;
            }else{
                bantu2->next=tmp;
            }
            bantu=tmp;
            bantu2 = bantu;
            bantu = bantu->next;
        }
    }
}

void urutkanMenurun(){
    node *tmp;
    bantu = awal;
    for(int i=0;i<indeks;i++){
        bantu=bantu2=awal;
        while(bantu->next!=NULL){
            if(bantu->data.npm<bantu->next->data.npm){
                tmp = bantu->next;
                bantu->next = bantu->next->next;
                tmp->next = bantu;
                if(bantu==awal){
                    awal=bantu2=tmp;
                }else{
                    bantu2->next=tmp;
                }
                bantu=tmp;
            }
            bantu2 = bantu;
            bantu = bantu->next;
        }
    }
}

void ulang(){
    indeks = -1;
    awal=akhir=NULL;
}

bool cekUrutMenaik(){
    if(indeks == -1 || indeks == 0){
        return true;
    }

    bantu = awal;
    for(int i=0;i<indeks;i++){
        if(bantu->data.npm > bantu->next->data.npm ){
            return false;
        }
        bantu=bantu->next;
    }
    return true;
}

bool cekUrutMenurun(){
    if(indeks == -1 || indeks == 0){
        return true;
    }

    bantu = awal;
    for(int i=0;i<indeks;i++){
        if(bantu->data.npm < bantu->next->data.npm ){
            return false;
        }
        bantu=bantu->next;
    }
    return true;
}

node *cariTengah(node *awalNode,node *akhirNode){
    if(awalNode == NULL){
        return NULL;
    }

    node *sekarang = awalNode;
    node *depan = awalNode->next;

    while(depan!=akhirNode){
        depan = depan->next;
        if(depan!=akhirNode){
            sekarang = sekarang->next;
            depan = depan->next;
        }
    }
    return sekarang;
}

void cari(){
    if(cekUrutMenaik() || cekUrutMenurun()){
        bantu = awal;
        bantu2 = NULL;
        int cariNpm;
        cout << "Masukkan npm yang mau di cari : ";
        cin >> cariNpm;

        do{
            node *tengah = cariTengah(bantu,bantu2);

            if(tengah == NULL){
                cout << "Data kosong" << endl;
                system("pause");
                break;
            }

            if(tengah->data.npm == cariNpm){
                cout << "Data ditemukan pada index ke-" << tengah->index << endl;
                cout << "NPM \t: " << tengah->data.npm << endl << "Nama \t: " << tengah->data.nama << endl;
                system("pause");
                break;
            }

            if(cekUrutMenaik() == true && cekUrutMenurun() == false){
                if(tengah->data.npm < cariNpm){
                    bantu = tengah->next;
                }else{
                    bantu2 = tengah;
                }
            }else{
                if(tengah->data.npm > cariNpm){
                    bantu = tengah->next;
                }else{
                    bantu2 = tengah;
                }
            }


        }while(bantu2==NULL || bantu2->next != bantu);
    }else{
        cout << "Data belum urut.. Mohon pilih menu 2 atau 3 untuk mengurutkan..." << endl;
        system("pause");
    }
}

void buatData(){
    ulang();
    int jum;
    cout << "Masukkan jumlah data yang ingin di buat : ";
    cin >> jum;

    string nama;
    char huruf = 'a';
    int npm = 1;
    for(int i=1;i<=jum;i++){
        nama = huruf;
        buatNode(nama,npm);
        huruf++;
        npm++;
    }
}

int main()
{
    int menu;
    do{
        system("cls");
        view();
        cout << endl << endl;
        cout << "Menu : " << endl;
        cout << "1. Tambah Data" << endl;
        cout << "2. Urutkan Menaik" << endl;
        cout << "3. Urutkan Menurun" << endl;
        cout << "4. Acak" << endl;
        cout << "5. Ulang" << endl;
        cout << "6. Cari" << endl;
        cout << "7. Buat Data Otomatis" << endl;
        cout << "8. Keluar" << endl;
        cout << "Masukkan menu :";
        cin >> menu;

        if(menu == 1){
            tambahData();
        }else if(menu == 2){
            urutkanMenaik();
        }else if(menu == 3){
            urutkanMenurun();
        }else if(menu == 4){
            acak();
        }else if(menu == 5){
            ulang();
        }else if(menu == 6){
            cari();
        }else if(menu == 7){
            buatData();
        }

    }while(menu != 8);
}