Expert: vijayan - 4/20/2009

Question
I was the following...

Write a program that displays a menu with the following choices to the user.
    A - Find the largest # with a known quantity of numbers
    B - Find the smallest # with an unknown quantity of numbers
    C - Quit
Please enter your choice ___

This menu needs to be repeatedly displayed until the user chooses to quit.

If A is chosen, you should ask the user how many numbers he wants to enter. If he enters 5, you should read 5 numbers from him. You should then display the largest number he entered. Use a for loop to read these and display the largest.
If B is chosen, you should keep reading numbers no matter what until the user enters -99. Then you should display the smallest number he entered not counting the -99.

can you help me get started?


Answer
revision: change to public

to find the largest number entered by a user, you do not need to store all the numbers in memory. this would do:

a. initially make the first number entered by the user the largest number.

int largest_so_far ;
std::cin >> largest_so_far ;

b. read the remaining numbers in a loop and check against the largest so far read.

begin loop:

   int number ;
   std::cin >> number ;  
   if( largest_so_far < number ) largest_so_far = number ;

end loop

the only difference between options A and B is the kind of loop you would write.

A:
   int N ; // how many numbers
   std::cin >> N ;

   int largest_so_far ;
   std::cin >> largest_so_far ; // read first number

   for( int i=1 ; i<N ; ++i ) // read remaining N-1 numbers
   {
       // ...
   }    


B:
   int largest_so_far ;
   std::cin >> largest_so_far ; // read first number

   int number ;
   while( ( std::cin >> number ) && ( number != -99 ) )
   {
       // ...  
   }