E-book how to solve

4.1
#include <iostream>
#include <stdlib.h>
using namespace std;
int main(void)
{
       int A[5] = {5, 10, 6, 0, 4};
       int B[5] = {0, 0, 0, 0, 0};
       int i;
       // Nilai array A integer
       cout<<"Nilai dari array A: ";
       for(i=0; i<5; i++){
              cout<<A[i];
       }
       //
       for(i=0; i<5; i++){
              B[4-i] = A[i];
       }
       // Output
       cout<<"\n";
       cout<<"Nilai dari array B hasil dari membalikkan nilai array A :\n";
       for(i=0; i<5; i++){
              cout<<B[i];
       }
       cout<<"\n";
     
       system("pause");
       return(0);
}


4.2
#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;
int main(int argc, char** argv) {
int banyak, i,x;
int nilai[20];
string nama;
cout<<"Masukan Banyak Mahasiswa :"; cin>>banyak;

for (int i=1;i<=banyak;i++){
cout<<"nama Mahasiswa :";cin>>nama;
cout<<"Masukan nilai  :";cin>>nilai[20];

if (nilai[20]>=80 || nilai[20]<=100){
cout<<"\n Nilai "<<nilai[20]<<"Adalah A";
}
else if (nilai[20]>=60 || nilai[20]<80){
cout<<"\n Nilai "<<nilai[20]<<"Adalah B";
}
else if (nilai[20]>=40 || nilai[20]<60){
cout<<"\n Nilai "<<nilai[20]<<"Adalah C";
}
else if (nilai[20]>=20 || nilai[20]<40){
cout<<"\n Nilai "<<nilai[20]<<"Adalah D";
}
else if (nilai[20]>=0 || nilai[20]<20){
cout<<"\n Nilai "<<nilai[20]<<"Adalah E";
}
cout<<"\n========================================================================\n";
}
return 0;
}

4.3
#include <cstdlib>
#include <iostream>
#include <math.h>
using namespace std;


int main(int argc, char *argv[])
{
int a,b,c,d,bersih,pokok,pajak;
int pendapatan,beban;
int laba_usaha,laba_kotor,laba_sebelum_pajak,laba_bersih;
cout<<"|====================================================|\n";
cout<<"|                                                    |\n";
cout<<"|          Program Untuk Mencari Laba Usaha          |\n";
cout<<"|                                                    |\n";
cout<<"|====================================================|\n";
cout<<"| Mencari Pendapatan                                 |\n";
cout<<"|----------------------------------------------------|\n";
cout<<"| Masukkan pendapatan usaha         : ";cin>>a;
cout<<"| Masukkan pendapatan di luar usaha : ";cin>>b;
pendapatan=a+b;
cout<<"| Jumlah pendapatan usaha           : "<<pendapatan<<"\n";
cout<<"|----------------------------------------------------|\n";
cout<<"| Mencari Beban                                      |\n";
cout<<"|----------------------------------------------------|\n";
cout<<"| Masukkan beban usaha \t\t: ";cin>>c;
cout<<"| Masukkan beban di luar usaha  : ";cin>>d;
beban=c+d;
cout<<"| Jumlah beban \t\t\t: "<<beban<<"\n";
cout<<"|----------------------------------------------------|\n";
cout<<"| Mencari Laba                                       |\n";
cout<<"|----------------------------------------------------|\n";
cout<<"| Masukkan penjualan bersih     : ";cin>>bersih;
cout<<"| Masukkan harga pokok    \t: ";cin>>pokok;
cout<<"| Masukkan pajak     \t\t: ";cin>>pajak;
cout<<"|----------------------------------------------------|\n";
cout<<"| Hasil Laba                                         |\n";
cout<<"|----------------------------------------------------|\n";
laba_kotor=bersih-pokok;
cout<<"| Laba Kotor \t\t: "<<laba_kotor<<"\n";
laba_usaha=laba_kotor-c;
cout<<"| Laba Usaha \t\t: "<<laba_usaha<<"\n";
laba_sebelum_pajak=laba_usaha+(b-d);
cout<<"| Laba Sebelum Usaha    : "<<laba_sebelum_pajak<<"\n";
laba_bersih=laba_sebelum_pajak-(pajak*15/100);
cout<<"| Laba Bersih \t\t: "<<laba_bersih<<"\n";
cout<<"|====================================================|\n";

system("pause");
return 0;
}


4.4
#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;
int main(int argc, char** argv) {
int a[20],n;
cout<<"Batas : ";
cin>>n;

for (int i=0;i<n;i++){
cout<<"Data : ";
cin>>a[i];
}
for (int i=0;i<n;i++){
if(a[i]==a[i+1])
cout<<a[i];
else if(a[i-1]==a[i])
cout<<"";
else if(a[i]==a[i+2])
cout<<a[i];
else if(a[i-2]==a[i])
cout<<"";
else if(a[i]==a[i+3])
cout<<a[i];
else if(a[i-3]==a[i])
cout<<"";
else if(a[i]==a[i+4])
cout<<a[i];
else if(a[i-4]==a[i])
cout<<"";
else if(a[i]==a[i+5])
cout<<a[i];
else if(a[i-5]==a[i])
cout<<"";

else
cout<<a[i];
}

/* for (int i=0;i<n;i++){
cout<<a[i]<<" ";


}*/

return 0;
}

4.5.1
#include <iostream>
#include <stdio.h>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

int main() {

    int n, *arr, onee = 0, twoo, threee, total = 0, maxx = -1, temp_maxx;

    cin >> n;
    arr = new int[n];

    for (int i = 0; i < n; i++) {
        cin >> arr[i];
        total += arr[i];
    }

    // O(n^2) is the following

    for (int i = 1; i < n - 1; i++) {
        onee += arr[i - 1];
        twoo = 0;
        for (int j = i + 1; j < n; j++) {
            twoo += arr[j - 1];
            threee = total - twoo - onee;
            temp_maxx = max(max(onee, twoo), threee);
            if ((temp_maxx < maxx) || (maxx == -1))
                maxx = temp_maxx;
        }
    }

    cout << maxx;

    return 0;
}

4.5.3
#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

//Bucket Sort
void bucket_sort (int arr[], int n)
{
  //Here range is [1,100]
  int m = 101;

  //Create m empty buckets
  int buckets[m];

  //Intialize all buckets to 0
  for (int i = 0; i < m; ++i)
    buckets[i] = 0;

  //Increment the number of times each element is present in the input
  //array. Insert them in the buckets
  for (int i = 0; i < n; ++i)
    ++buckets[arr[i]];

  //Sort using insertion sort and concatenate
  for (int i = 0, j = 0; j < m; ++j)
    for (int k = buckets[j]; k > 0; --k)
      arr[i++] = j;
}


//Driver function to test above function
int main()
{
  int input_ar[] = {10, 24, 22, 62, 1, 50, 100, 75, 2, 3};
  int n = sizeof (input_ar) / sizeof (input_ar[0]);
  bucket_sort (input_ar, n);

  cout << "Sorted Array : " << endl;
  for (int i = 0; i < n; ++i)
    cout << input_ar[i] << " ";

return 0;
}

4.6
#include <stdio.h>
#include<iostream>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

main() {
int x;
int y;
cout<<"\nMasukkan bilangan ke- 1 :";
cin>>x;
cout<<"Masukkan bilangan ke-2 :";
cin>>y;
if(x>y){

cout<<"lebih besar dari pada\n\n ";cin>>x,y;
}else if(x=y){
cout<<"sama besar dengan\n\n";cin>>x,y;

}else{
cout<<"lebih kecil dari pada\n\n";cin>>x,y;
}

return 0;
}