program to find factorial, sum, sum of odd, series

#include<iostream.h>
#include<conio.h>
#include<math.h>
void sum1(int);
void odd(int);
void sum3(int,int);
int fact(int);
void main()
{
    int a,n,x;
    clrscr();
    cout<<"enter the value of n";
    cin>>n;
    cout<<"enter the value of x for series ";
    cin>>x;
    cout<<"the sum of series 1 is ";
    sum1(n);
    cout<<"\nsum of n odd numbers ";
    odd(n);
    cout<<"\nsum of series 3rd ";
    sum3(n,x);
    getch();
}
void sum1(int n)
{
    int sum=0,i,j;
    for(i=1;i<=n;i++)
    {
    sum+=i;
    }
    cout<<sum;
}
void odd(int n)
{
    int sum=0,i;
    for(i=1;i<=n;i=i+2)
    {
        sum+=i;
    }
    cout<<" "<<sum;
}
void sum3(int n,int x)
{
    int i;
    float sum=x;
    for(i=2;i<=n;i=i+2)
    {
        sum+=(pow(x,i))/fact(i);
    }
    cout<<" "<<sum;
}
int fact(int x)
{
    int y;
    if((x==0)||(x==1))
    {
        return(1);
    }
    else
    {
        y=x*fact(x-1);
    }
    return(y);
}