Writing an array-sorting algorithm has been the bane of intro-C++ courses since the language was invented, I think. Being a hobbyist, I try to avoid having to sort. If you just need the max and min,...

What I would do is this instead of the "read" loop:

int tmax, tmin;

tmax=temp[0];
tmin=temp[0];

for(int i=0; i<31; i++){
if(temp[i]>tmax){
tmax=temp[i];