I have to redo Programming Exercise 5 of Chapter 9 using dynamic arrays. I have the problem but I don't know how to use it using dynamic arrays please help.
//Chapter 9: Programming Exercise 5
#include <iostream>
#include <cstring>
#include <cctype>
using namespace std;
int main()
{
char str[81];
int len;
int i;
cout << "Enter a string: ";
cin.get(str, 80);
cout << endl;
cout << "String in upper case letters is:" << endl;
len = strlen(str);
for (i = 0; i < len; i++)
cout << static_cast<char>(toupper(str[i]));
cout << endl;
return 0;
}