lave dette til void stringcat(char[], char[])

Hej med jer,
Er der nogle der kan hjaelpe mig med dette? Jeg skal samle functioner:
int strlen( const char str[] );
bool stringcat(char str_a[], const char str_b[], int a_len);

i EN function:
void stringcat(char[],char[]);
de system-definerede functioner strlen, strcmp og strcpy maa IKKE benyttes.
Jeg har sat pointene til 100, da jeg skal aflevere snarest muligt - helst igaar:)
Nedenfor er programmet.

Paa forhaand tak!





//function protypes
int strlen( const char str[] );
bool stringcat(char str_a[], const char str_b[], int a_len);


void main()
{
    // variables used
    char string_a[128] = "Cheese cake";
    char string_b[128] = " is good!";

    cout << "str a: " << string_a << endl;
    cout << "str b: " << string_b << endl;

    //funtion call in the if statement for function stringcat
    if( stringcat( string_a, string_b, sizeof(string_a) ) )
    {
        cout << "stringcat a: " << string_a << endl;
       
    }
    else
    {
        cout << "stringcat: failed" << endl;
    }

}

// has to be NULL terminated
int strlen( const char str[] )
{
    int i=0;

    while( true )
    {
        //test if this element is a NULL termination
        if( str[i] == '\0' )
        {

            // size without NULL termination
            return i;
        }

        i++;
    }
}

bool stringcat( char str_a[], const char str_b[], int a_len )
{
    //The lenght of a minus NULL termination
    int a_size = strlen( str_a );

    //The lenght of b minus NULL termination
    int b_size = strlen( str_b );

    //Total lenght of both strings+ space for NULL termination
    int total = a_size + b_size + 1;
   
    //is there space enough for both strings + NULL
    //termination in string a?
    if( total > a_len )
    {
        // not enough space
        return false;
    }

    for( int i=0; i<b_size; i++ )
    {
        //put b into a at the first empty spot in a's string
        str_a[a_size+i] = str_b[i];
    }
    // terminate string a right after string b
    str_a[a_size+b_size+1] = '\0';
   
    return true;
}