如何清空特定的char数组位置

I have a 200-elements-long char array, I load the vector with new characters in a loop, and at each cycle the element number can be different from the previous one, so how can I empty the unwanted position of the array? Note: the element size have to be of 200 and I can't resolve the problem creating a new instance of the object with new.I have a 200-elements-long char array, I load t