How to solve it by computer 4.2

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

Program C++

#include <iostream>

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;

}