Fixed PointI teration Method

#include<bits/stdc++.h>
using namespace std;
int It=6;
double v;
// Fixed POINT METHOD

double x,y,z;

double First_Equation (){
   // return 2-(x*x);
   return 5/x;
}

double Second_Equation (){
    return (y*y)+y-5;
}

double Third_Equation (){

    return (z+(5/z))/2;
}

void solve(){
    int ok=0,i=0;
    v=0;
    while(true){
        long double F=First_Equation();
         cout<<"Iteration "<<++i<<": "<<F<<"\n";
         x=F;
          if(It==ok) break;
         if(v-F==0){ break;goto S;}
         v=F;
         ok++;
    }
    cout<<"\n\n";
    ok=0,v=0,i=0;
    while(true){
        long double F=Second_Equation();
         cout<<"Iteration "<<++i<<": "<<F<<"\n";
         y=F;
          if(It==ok) break;
         if(v-F==0){ break;goto S;}
         v=F;
         ok++;
    }

    cout<<"\n\n";
    ok=0,v=0,i=0;
    while(true){
        long double F=Third_Equation();
         cout<<"Iteration "<<++i<<": "<<F<<"\n";
         z=F;
         if(It==ok) break;
         if(v-F==0){ break;goto S;}
         v=F;
         ok++;
    }
    S:
    cout<<"\n"<<"Solution: "<<v<<"\n";
}


int main()
{
    cin>>x;
    cin>>y;
    cin>>z;
    solve();

    return 0;
}