c++_ calculator

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#include<iostream>
#include<math.h>
using namespace std;
                                               // FUNCTION PROTOTYPES
int cube (int x);
int Sum(int a,int b);
int multiply(int x, int y);
int subtract(int a, int b);
int square (int x);
int Divide(int a , int b);
int fraction (int a, float ans);
int power(int x, int y );
double squarroot(double x,double ans);

void main()                                  // MAIN FUNCTION
{
int number1=0;
int number2=0;
int menu;
float ans=0;
int ans2=0;
cout<<"please follow the instructions"<<endl;
    cout<<"Press 1 for to calculate cube"<<endl;
cout<<"press 2 to calculate sum"<<endl;
cout<<"Press 3 to calculate multiplication"<<endl;
cout<<"Press 4 to calculate divison"<<endl;
cout<<"Press 5 to calculate subtraction"<<endl;
    cout<<"presss 6 to calculate square"<<endl;
cout<<"Press 7 to calculate invert of a number"<<endl;
cout<<"Press 8 to calculate square root"<<endl;
cout<<"Press 9 to calculate power"<<endl;
cin>>menu;
if (menu == 1)
{
    cout<<"Enter NUMBER";
    cin>>number1;
   cout<<"ANS IS: "<<cube (number1)<<endl;
}
else if (menu==2)
{  cout<<"Enter Number to calculate sum"<<endl;
   cin>>number1>>number2;
   cout<<"Answer is :"<<Sum(number1,number2)<<endl;
}
else if(menu==3)
{ cout<<"Enter Number to calculate multiplication"<<endl;
  cin>>number1>>number2;
  cout<<"Answer is :"<<multiply(number1,number2)<<endl;
}
else if(menu ==4 )
{   cout<<"Enter numbers to divide"<<endl;
   cin>>number1>>number2;
   cout<<"Answer is: "<<Divide (number1,number2)<<endl;
}
else if(menu==5)
{   cout<<"Enter numbers to subtract"<<endl;
    cin>>number1>>number2;
cout<<"Answer is: "<<subtract(number1,number2)<<endl;
}
else if(menu==6)
{
cout<<"enter the Number to calculate the sqaure"<<endl;
cin>>number1;
cout<<"Answer is :"<<square(number1);
}
else if(menu==7)
{   cout<<"Enter the number to calculate its invert i.e 1/number"<<endl;
    cin>>number1;
ans=1/number1;
cout<<"Answer is :"<<fraction(number1,ans);
}
else if(menu==8)
{
cout<<"Enter the number to calculate its square root"<<endl;
cin>>number1;
cout<<"Answer is :"<<squarroot(number1)<<endl;
}
else if(menu==9)
{
cout<<"enter the number and other number to calculate its power"<<endl;
cin>>number1>>number2;
cout<<"Answer is:"<<power(number1,number2)<<endl;
}


}
int Sum(int a,int b)
{  
return(a+b);
}
int multiply(int x, int y)
{  
return(x*y);
}
int subtract(int a, int b)
{
return(a-b);
}
int square (int x)
{
return (x*x);
}
int cube (int x)
{
return (x*x*x);
}
int fraction (int a, float ans)
{
   ans=(1/a);
   return (ans);
}
int Divide(int a , int b)
{
return(a/b);
}

double squarroot(double x,double ans)
{ ans==sqrt(x);
  return (ans);
}
int power(int x, int y )
{  int sum;
sum = 1;
for (int i=0; i<y; i++)
{
sum *= x;
}
return (sum);
}