Pseudo-code
To find average, min and max among a list.
First, you initialise sum to zero, min to a very big number, and max to a very small number.
Then, you enter the numbers, one by one.
For each number that you have entered, assign it to num and add it to the sum.
At the same time, you compare num with min, if num is smaller than min, let min be num instead.
Similarly, you compare num with max, if num is larger than max, let max be num instead.
After all the numbers have been entered, you divide sum by the numbers of items entered, and let ave be this result.