Подскажите ,как осуществить поиск максимального элемента массива

#include <iostream>
#include <conio.h>
#include <fstream>
 
using namespace std;
 
int main()
{
 
 float a,b,c;
 
 ifstream fin("z1.txt");
  c=a+b;
 
 cout<<"с="<<c;
 fin>>c;
 
  fin.close();
 
 
  cout<<endl<<"Press any key to finish...";
  getch();
  return 0;

#include <iostream>
#include <conio.h>
#include <fstream>
 
using namespace std;
 
int main()
{
 
  float a,b,c;
  ifstream fin("z1.txt", ios::in);
  fin>>a>>b;
  c = a + b;
  cout<<"c="<<c<<endl;
  fin.close();
  cout<<endl<<"Press any key to finish...";
  getch();
  return 0;
}

for(int i=size-1;i!=0;i--){}

#include <iostream>
#include <conio.h>
#include <fstream>
 
using namespace std;
 
int main()
{
 
 
  float a;
  int i;
  const int n=20;
 
  ifstream fin("abc_in.txt");
  ofstream fout("abc_out.txt");
 
  cout<<"Array_reverse() a ["<<20<<"]:"<<endl;
  i=0;
  while (i<n)
  {
    fin>>a;
    fout<<a<<"  ";
    i++;
  }
 
 
 
 
  fout.close();
  fin.close();
 
  cout<<endl<<"Results in the file \"abc_out.txt\" ";
  cout<<endl<<"Press any key to finish...";
  getch();
  return 0;
}

 #include <conio.h>
 #include <fstream>
 using namespace std;
  int main() {
 float a;
 int i;
 const int n=20;
 int temp[n];
 ifstream fin("abc_in.txt");
 ofstream fout("abc_out.txt");
 
 cout<<"Array_reverse() a ["<<20<<"]:"<<endl;
 for (i=0;i<n;i++)
     fin>>temp[i];
 for (i=n-1;i>=0;i--)
     fout<<temp[i]<<" ";
 fout.close();
 fin.close();
 
 cout<<endl<<"Results in the file \"abc_out.txt\" ";
 cout<<endl<<"Press any key to finish...";
 getch();
 return 0;
 }

int main()
{
 
 
  float a;
  double i; // <---
  const int n=20;
 
  ifstream fin("abc_in.txt");
  ofstream fout("abc_out.txt");
 
  i=0;
  while (i<n)
  {
    fin>>a;
    fout<<a<<"  ";
    i++;
  }
 
 
 
  fout.close();
  fin.close();
 
  cout<<endl<<"Results in the file \"abc_out.txt\" ";
  cout<<endl<<"Press any key to finish...";
  getch();
  return 0;
}

 #include <iostream>
 #include <conio.h>
 #include <fstream>
 
  using namespace std;
 
  int main()
 
{
  float a;
  int i;
  const int n=20;
  int temp[n];
  ifstream fin("abc_in.txt");
  ofstream fout("abc_out.txt");
 
 
 
  cout<<"Array_reverse() a ["<<20<<"]:"<<endl;
  for (i=0;i<n;i++)
     fin>>temp[i];
  for (i=n-1;i>=0;i--)
     fout<<temp[i]<<" ";
  fout.close();
  fin.close();
 
 cout<<endl<<"Results in the file \"abc_out.txt\" ";
 cout<<endl<<"Press any key to finish...";
 getch();
 return 0;

double temp[n];