Mencari nilai rata-rata dan grade score

#include <iostream>
using namespace std;
main(){
string nama;
string nim;
int nilai_tugas;
int nilai_quiz;
int nilai_mid;
int nilai_uas;
int rata;
char grade;

cout<<"===========program nilai==========="<<endl;
cout<<"masukan nama anda :";cin>>nama;
cout<<"masukan nim anda :";cin>>nim;
cout<<"masukan nilai tugas :";cin>>nilai_tugas;
cout<<"masukan nilai quiz :";cin>>nilai_quiz;
cout<<"masukan nilai mid :";cin>>nilai_mid;
cout<<"masukan nilai uas :";cin>>nilai_uas;
cout<<"====================================="<<endl;
//=======================================================================
rata=(0.2*nilai_tugas)+(0.2*nilai_quiz)+(0.3*nilai_mid)+(0.3*nilai_uas);
//=======================================================================
cout<<"nama  anda :"<<nama<<endl;
cout<<"nim anda :"<<nim<<endl;
cout<<"nilai tugas anda :"<<nilai_tugas<<endl;
cout<<"nilai tugas anda :"<<nilai_quiz<<endl;
cout<<"nilai tugas anda :"<<nilai_mid<<endl;
cout<<"nilai tugas anda :"<<nilai_uas<<endl;
cout<<"====================================="<<endl;
if(rata>=80){
grade='A';
}
else if(rata>=60){
grade='B';
}
else if(rata>=40){
grade='C';
}
else if(rata>=20){
grade='D';
}
else{
grade='E';
}

cout<<"nilai rata rata anda :"<<rata<<endl;
cout<<"grade score anda :"<<grade;

}