I think this would work:
#include <iostream>
using namespace std;
int main()
{
///////////////////////////////Creating variables/////////////////////////////////////
int number = 0;
int min, max;
///////////////////////////////Blah!Blah!Blah!Blah!///////////////////////////////////
cout << "This program will let you enter number after\n";
cout << "number. Enter 99 when you want to quit the ";
cout << "loop.\n";
///////////////////////For initialising values of min and max////////////////////////
cin>>number;
if(number==99) return(0); //if the number is 99 the program will quit
min = max = number; //initialize the values of min and max to compare with later inputs
///////////////////////////Loop to get the numbers/////////////////////////////////
while(number!=99) //loop
{
cin>>number;
/////////////////////////////Evaluating the numbers/////////////////////////////////
if(number ==99) break; //break the loop or else max will become 99 if this line is not there
else if(number>max) max = number; //if the no. is greater than max then it becomes the max
else if(number<min) min = number; // if the no. is smaller than min then it becomes min
} //end of loop
////////////////////Printing the smallest and biggest numbers/////////////////////
cout<<"The smallest number is: "<<min<<endl; //displays smallest no.
cout<<"The biggest number is: "<<max<<endl; //displays biggest no.
return 0;
}