Bạn nên học C/C++ một cách bài hản. Thường nhưng người học 1 ngôn ngữ rồi sau đó học một ngôn ngữ khác hanh gặp vấn đề về phong cách code.
float a,b,c,d,f,e,r,m; // Hạn chế khai báo biến toàn cục
int p; // Đặt tên biến rõ ràng.
using namespace std;
int main(){
cout << "Giai Hinh \n";
cout << " ------------------------------------\n";
cout << " 1.Hinh Chu Nhat\n";
cout << " 2.Hinh Vuong\n ";
cout << " 3.Hinh Thoi\n ";
cout << " 4.Hinh Binh Hanh\n ";
cout << " 5.Hinh Thang\n ";
cout << " 6.Hinh Tron\n ";
cout << " 7.Thong Tin Chuong Trinh\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> p;
system("cls");
if(p==1){
cout << " Hinh Chu Nhat \n";
cout << " ------------------------------------\n";
cout << " @--Tinh Dien Tich--@\n";
cout << " 1.Dien Tich\n ";
cout << " 2.Chu Vi\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> a; // Chia lamf các hàm riêng.
system("cls");
if (a==1){ // Chỗ này dùng swich case.
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Chieu Dai :\n";
cin >> b;
system("cls");
cout << "Chieu Rong :\n";
cin >> c;
system("cls");
d=b*c; // Tách roid model view và control ra.
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La S Cua Hinh Chu Nhat\n";
cout << " ------------------------------------ \n";
}
else if (a==2){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Chieu Dai :\n";
cin >> e;
system("cls");
cout << "Chieu Rong :\n";
cin >> r;
system("cls");
f=((e+r)*2);
system("cls");
cout << f << endl;
cout << " ------------------------------------ \n";
cout <<"La C Cua Hinh Chu Nhat\n";
cout << " ------------------------------------ \n";
}
else if (a>=3){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}
else if(p==2){
cout << " Hinh Vuong \n";
cout << " ------------------------------------\n";
cout << " @--Tinh Dien Tich--@\n";
cout << " 1.Dien Tich\n ";
cout << " 2.Chu Vi\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> a;
system("cls");
if (a==1){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Chieu 1 Canh :\n";
cin >> b;
system("cls");
d=b*b;
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La S Cua Hinh Vuong\n";
cout << " ------------------------------------ \n";
}
else if (a==2){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Chieu 1 Canh :\n";
cin >> e;
system("cls");
f=e*4;
system("cls");
cout << f << endl;
cout << " ------------------------------------ \n";
cout <<"La C Cua Hinh Vuong\n";
cout << " ------------------------------------ \n";
}
else if (a>=3){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}
else if(p==3){
cout << " Hinh Thoi \n";
cout << " ------------------------------------\n";
cout << " @--Tinh Dien Tich--@\n";
cout << " 1.Dien Tich\n ";
cout << " 2.Chu Vi\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> a;
system("cls");
if (a==1){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Duong Cheo 1 :\n";
cin >> b;
system("cls");
cout << "Duong Cheo 2 :\n";
cin >> c;
system("cls");
d=((b*c)*1/2);
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La S Cua Hinh Thoi\n";
cout << " ------------------------------------ \n";
}
else if (a==2){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Chieu 1 Canh :\n";
cin >> e;
system("cls");
f=e*4;
system("cls");
cout << f << endl;
cout << " ------------------------------------ \n";
cout <<"La P Cua Hinh Thoi\n";
cout << " ------------------------------------ \n";
}
else if (a>=3){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}
else if(p==4){
cout << " Hinh Binh Hanh \n";
cout << " ------------------------------------\n";
cout << " @--Tinh Dien Tich--@\n";
cout << " 1.Dien Tich\n ";
cout << " 2.Chu Vi\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> a;
system("cls");
if (a==1){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Duong Cao :\n";
cin >> b;
system("cls");
cout << "Canh Day :\n";
cin >> c;
system("cls");
d=b*c;
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La S Cua Hinh Binh Hanh\n";
cout << " ------------------------------------ \n";
}
else if (a==2){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Canh Ke 1 :\n";
cin >> e;
system("cls");
cout << "Canh Ke 2 :\n";
cin >> r;
system("cls");
f=((e+r)*2);
system("cls");
cout << f << endl;
cout << " ------------------------------------ \n";
cout <<"La C Cua Hinh Binh Hanh\n";
cout << " ------------------------------------ \n";
}
else if (a>=3){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}
else if(p==5){
cout << " Hinh Thang \n";
cout << " ------------------------------------\n";
cout << " @--Tinh Dien Tich--@\n";
cout << " 1.Dien Tich\n ";
cout << " 2.Chu Vi\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> a;
system("cls");
if (a==1){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Duong Cao :\n";
cin >> b;
system("cls");
cout << "Canh Day 1 :\n";
cin >> c;
system("cls");
cout << "Canh Day 2 :\n";
cin >> e;
system("cls");
d=b*((c+e)/2);
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La S Cua Hinh Thang\n";
cout << " ------------------------------------ \n";
}
else if (a==2){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Canh Ke 1 :\n";
cin >> e;
system("cls");
cout << "Canh Ke 2 :\n";
cin >> r;
system("cls");
cout << "Canh Ben 1 :\n";
cin >> b;
system("cls");
cout << "Canh Ben 2 :\n";
cin >> c;
system("cls");
f=e*r*b*c;
system("cls");
cout << f << endl;
cout << " ------------------------------------ \n";
cout <<"La P Cua Hinh Thang\n";
cout << " ------------------------------------ \n";
}
else if (a>=3){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}
else if(p==6){
cout << " Hinh Tron \n";
cout << " ------------------------------------\n";
cout << " @--Tinh Dien Tich--@\n";
cout << " 1.Dien Tich\n ";
cout << " 2.Chu Vi\n ";
cout << " Nhap Stt:\n";
cout << " ------------------------------------ \n";
cin >> a;
system("cls");
if (a==1){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Ban Kinh :\n";
cin >> b;
system("cls");
cout << "Duong Kinh :\n";
cin >> c;
d=b*b*3.14;
m=(c*c*3.14)/4;
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La S Cua Hinh Tron(Theo R)\n";
cout << " ------------------------------------ \n";
cout << m << endl;
cout << " ------------------------------------ \n";
cout <<"La A Cua Hinh Tron(Theo D)\n";
cout << " ------------------------------------ \n";
}
else if (a==2){
cout << " Loading........\n";
cout << " ------------------------------------ \n";
system("pause");
system("cls");
cout << "Ban Kinh :\n";
cin >> b;
system("cls");
cout << "Duong Kinh :\n";
cin >> c;
d=2*b*3.14;
m=c*3.14;
system("cls");
cout << d << endl;
cout << " ------------------------------------ \n";
cout <<"La C Cua Hinh Tron(Theo R)\n";
cout << " ------------------------------------ \n";
cout << m << endl;
cout << " ------------------------------------ \n";
cout <<"La C Cua Hinh Tron(Theo D)\n";
cout << " ------------------------------------ \n";
}
else if (a>=3){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}
else if (p==7){
cout << " ------------------------------------\n";
cout << " Phien Ban 1.0\n\n";
cout << " Edit Code C++ By Poliun\n\n";
cout << " MS-54654165165454165\n\n";
cout << " Chuc Ban Mot Ngay Toan Lanh\n\n";
cout << " ------------------------------------ \n";
system("pause");
return 0;
}
else if (p>=8){
cout << "Error\n";
system("pause");
exit(0);
}
system("pause");
return 0;
}