如何在快速数组中计算元素的出现?

I've seen a few examples of this but all of those seem to rely on knowing which element you want to count the occurrences of. My array is generated dynamically so I have no way of knowing which element I want to count the occurrences of (I want to count the occurrences of all of them). Can anyone advise?I've seen a few examples of this but all of tho