VirtualWire

There is no string datatype in C - strings are just "char" arrays, with the last position filled with a zero (A true zero, not an ASCII zero).
So, the string "Hello" occupies six consecutive locations in array, 'H', 'e', 'l', 'l', 'o' with '\0', where the backslash signifies to the compiler that is really is zero, not ASCII zero.