How can I correct this error in mfc?

My code is:

    CString testArray[5];
    for (int i = 0; i < 5; i++)
    {
        testArray[i].Format("%d", i*4);
    }

    memmove(testArray[2], testArray[3], sizeof(testArray)-2*sizeof(testArray[0]));

    for (int i = 0; i < 5; i++)
    {
        MessageBox(testArray[i]);
    }

I compiled it in visual studio 2010, and I can see this error:

error C2664: 'memmove' : caot convert parameter 1 from 'CString' to 'void *'

How can I correct this error in mfc? Help me.