Функции в C++

#include <iostream.h>
long fibon(int);
main()
{
int n;
long m;
cout<<"enter n\n";
cin>>n;
m=fibon(n);
cout<<n<<"chlen="<<m<<"\n";
return 0;
}
long fibon(int a)
{
int x;
int i;
long s=0,a=1,b=1;
for (i=1;i<=x-2;i++)
{
s=a+b;
a=b;
b=s;
}
return s;
}

#include <iostream.h>
long fibon(int);
main()
{
int n;
long m;
cout<<"enter n\n";
cin>>n;
m=fibon(n);
cout<<n<<"chlen="<<m<<"\n";
return 0;
}
long fibon(int a)
{
int i;
long s=0;b=1,c=1;
for (i=1;i<=a-2;i++)
{
s=b+c;
b=c;
c=s;
}
return s;
}

{
int i,b,c;
long s=0;b=1,c=1;
for (i=1;i<=a-2;i++)
{
s=b+c;
b=c;
c=s;
}
return s;
}

#include <stdio.h>
#include <conio.h>
long int fib(int n){
    int i;
    long int a,b;
    for(a=1,b=1,i=3;i<=n; (a<=b)?(a+=b):(b+=a),i++);
    return((a>=b)? a:b);
}
 
main(){
    int n;
    printf("vvedite nomer chisla Fibonnaci ");
    scanf("%i",&n);
    printf("%ie chislo Fibonnaci %li",n,fib(n));
    getch();
}

#include <iostream.h>
#include <math.h>
double fact(int);
main()
{
double s=0;
int n,i,j=1,x;
cout<<"enter n and x\n";
cin>>n>>x;
for (i=1;i<=n;i++)
{
s=s+(exp(j*log(x)))/fact(j);
j+=1;
}
cout<<"e^"<<x<<"="<<s<<"\n";
return 0;
}
double fact(int a)
{
int k,m=1;
for (k=1;k<=a;k++)
m=m*k;
return m;
}

#include <iostream>
using namespace std;
double fact(int);
main()
{
double s=0;
int n,i,j=1,x;
cout<<"enter n and x\n";
cin>>n>>x;
for (i=1;i<=n;i++)
{
s=s+(exp(j*log(x)))/fact(j);
j+=1;
}
cout<<"e^"<<x<<"="<<s<<"\n";
return 0;
}
double fact(int a)
{
int k,m=1;
for (k=1;k<=a;k++)
m=m*k;
return m;
}