How to Solve 4.2

1.Algoritma :
   Deklarasi banyak,i,x
array int nilai [20]
deklarasi string nama

inputkan banyak mahasiswa
for (int i=1;i<=banyak;i++){
input nama;
input nilai mahasiswa i
if (nilai[20]>=80 || nilai[20]<=100)
ceta nilai = A
else if (nilai[20]>=60 || nilai[20]<80)
cetak nilai = B
else if (nilai[20]>=40 || nilai[20]<60)
cetak nilai = C
else if (nilai[20]>=20 || nilai[20]<40)
cetak nilai = D
else if (nilai[20]>=0 || nilai[20]<20)
cetak nilai = E
end for


2.c++:
#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;
}

how to solve 4.3-4.4 http://fafa145.blogspot.co.id/
how to solve 4.5-4.6 http://pengantarprogram.blogspot.co.id/