Factorial And Arithematic Operation in C++

#include<iostream>
#include<iomanip>
#include<cstdlib>
using namespace std;
int main()
{
int num1;
int num2;
char choice;
start :
cout<<setw(45)<<"Plz Select Options you needed :\n\n"<<endl;
cout<<"Press A to find sum of two numbers."<<endl;
cout<<"Press S to subtract two numbers."<<endl;
cout<<"Press M to multiple two numbers."<<endl;
cout<<"Press D to Divide two numbers."<<endl;
cout<<"Press F to find factorial of any number."<<endl;
cout<<"Press R to restart the program."<<endl;
cout<<"Press Y to End the Program"<<endl;
cout<<"\nDeveloped by:\n"<<setw(25)<<"zubair saif.."<<endl;
system("color 5f");
cin>>choice;
system("CLS");
switch(choice)
{
case 'y' :
return 0;
case 'a':
cout<<"Enter first number:";
cin>>num1;
cout<<"Enter second number:";
cin>>num2;
cout<<"The Sum is:\n ";
cout<<num1+num2;
cout<<"\n\nDeveloped by:\n"<<setw(25)<<"zubair saif.."<<endl;
cout<<endl;
goto start ;
case 's':
cout<<"Enter first number:";
cin>>num1;
cout<<"Enter second number:";
cin>>num2;
cout<<"Subtraction is:\n";
cout<<num1-num2;
cout<<"\n\nDeveloped by:\n"<<setw(25)<<"zubair saif.."<<endl;
cout<<endl;
goto start ;
break;
case 'm':
cout<<"Enter first number:";
cin>>num1;
cout<<"Enter second number:";
cin>>num2;
cout<<"MUltiplication is:\n";
cout<<num1*num2;
cout<<"\n\nDeveloped by:\n"<<setw(25)<<"zubair saif.."<<endl;
cout<<endl;
goto start ;
break;
case 'd':
cout<<"Enter first number:";
cin>>num1;
cout<<"Enter second number:";
cin>>num2;
cout<<"Divided is:\n";
cout<<num1/num2;
cout<<"\n\nDeveloped by:\n"<<setw(25)<<"zubair saif .."<<endl;
cout<<endl;
goto start ;
break;
case 'r':
goto start ;
break;
case 'f':
int g;
cout<< "Enter the value for finding factorial : ";
cin>>g;
cout<<"\n";
int fact = 1;
for(int i=1; i<=g;i++)
{
fact = fact * i;
}
cout<<"factorial of given number is "<<fact<<endl;
cout<<"\n\nDeveloped by:\n"<<setw(25)<<"zubair saif.."<<endl;
goto start ;
break;
system("CLS");
} 
}