CSE206 Week 5 - String Class

#include <iostream>
#include <cstdio>

using namespace std;
class String
{
    char * pt;
    int len;
public:
    String(int l)
    {
        len = l;
        pt = new char[len];
    }

    ~String()
    {
        delete [] pt;
    }

    String (const String& st)
    {
        len = st.len;
        pt = new char[len];
        for (int i = 0; i<len; i++)
            pt[i] = st.pt[i];
    }

    char get(int index)
    {
        if (index >= len || index < 0)
            return 0;
        else
            return pt[index];
    }
    int put(int index, char c)
    {
        if (index >= len || index < 0)
            return -1;
        else
            pt[index] = c;
    }
    int getLength()
    {
        return len;
    }
    void display()
    {
        for (int i = 0; i<len; i++)
            printf("%c", pt[i]);
        printf("\n");
    }
    friend void compare(String s1, String s2);
};
void compare(String s1, String s2)
{
    if (s1.getLength() > s2.getLength())
        cout << "The first string is greater"<<endl;
    else if (s1.getLength() < s2.getLength())
        cout << "The second string is greater"<<endl;
    else
        cout << "Both are equal"<<endl;
}
int main()
{
    String s1(4);
    String s2(5);
    String s3(5);
    s1.put(0, 'A');
    s1.put(1, 'B');
    s1.put(2, 'C');
    s1.put(3, 'D');
    s1.display();     //ABCD

    s2.put(0, '1');
    s2.put(1, '2');
    s2.put(2, '3');
    s2.put(3, '4');
    s2.display();     //1234

    compare(s1, s2);
    compare(s2, s1);
    compare(s2, s3);
}