Поменять местами максимальный элемент массива и первый

#include <iostream.h>
#include <vcl.h>
#include <conio.h>
#include <stdlib.h>
using namespace std;
int main()
{
int n,i;
float max=0;
cout <<"Enter integer value: ";
cin >> n;
float *p_darr=new float[n];
for (int i=0; i < n; i++) {
randomize;
p_darr[i]=(float)(rand())/RAND_MAX;
cout << "Value of " << i << " element is " << p_darr[i] << endl;}
for (i=0; i<n; i++){
if (p_darr[i]>max)
max=p_darr[i];
}
cout <<"Maks element = "<<max<<endl;
float b=p_darr[0];
p_darr[0]=max;
max=b;
for (int i=0; i < n; i++) {
cout << "Value of " << i << " element is " << p_darr[i] << endl;    }
delete [] p_darr;
system ("pause");
return 0;
}

#include <iostream>
#include <time.h>
using namespace std;
 
int main()
{
    srand (time(NULL));
    int n,i,k=0;
    float max=0;
    cout <<"Enter integer value: ";
    cin >> n;
    float *p_darr=new float[n];
    for (int i=0; i < n; i++) {
        p_darr[i]=((float)rand())/RAND_MAX;
        cout << "Value of " << i << " element is " << p_darr[i] << endl;
    }
    for (i=0; i<n; i++){
        if (p_darr[i]>max){
            max=p_darr[i];
            k=i;
        }
    }
    cout <<"Maks element = "<<max<<endl;
    float b=p_darr[0];
    p_darr[0]=max;
    p_darr[k]=b;
    for (int i=0; i < n; i++) {
        cout << "Value of " << i << " element is " << p_darr[i] << endl;    
    }
    delete [] p_darr;
    system ("pause");
    return 0;
}

#include <iostream>
#include <algorithm>
using namespace std;
 
int main ()
{
    int a[5] = {1,2,3,6,4};
    swap (a[0], *max_element (a, a + 5));
    for (int i = 0; i < 5; i++)
        cout <<a[i] <<endl;
    return 0;
}