when I try to assign \0 using the expression:

my compiler throws the following error: "invalid conversion from ‘const char*’ to ‘char’.

Any idea on what's wrong? Any idea on how to solve the problem?

That's because you enclosed the \0 in double quotes. Change it to single quotes pPtr->myArray[127]= '\0'; If myArray is less than 128 bytes then the above will cause buffer overflow.