help with strcpy and arrays with header file

I am tyring to do a programm that will use the function strcpy and i have to add the a header file in this code so far this is what i have but it's not doing what it should do
the output should say this
Hello
World............

Code:

---

#include <iostream.h>
#include <string.h>
#include "myStrcat.h"

int main ()
{
        char a[20];
        strcpy(a, "hello");
                myStrcat(a,"world");
        return 0;

}
char* myStrcat(char* dest, const char* src)
{
       
    int  i = strlen( src);
    while( *dest )
        src[i++];
        *dest++;
        src[i];
       
        return dest;


}

---

Think of it this way:
dest contains:

dest[0] = 'h';
dest[1] = 'e';
dest[2] = 'l';
dest[3] = 'l';
dest[4] = 'o';
dest[5] = '\0';

You want to copy into dest, starting at dest[5] (ie dest + strlen(dest) ), the string src, up to and including the terminating zero.

Does this work? No promises, I didn't compile, but I think it might...

Code:

---

char* mystrcat(char* dest, char* src)
{
    char* p = dest + strlen(dest);
    char* q = src;
    while ( *p++ = *q++ );
    return dest;
}

---

what should i put then in main function becuze this it compiles but it dosent give u nothing please help

Code:

---

int main ()
{
        char a[20];
        strcpy(a, "hello");
        mystrcat(a,"world");
                    cout<<"Output is: "<<a<<endl;
        return 0;

}

---

IfYouSaySo
thank you so much it works great see yaa