well, you can have a function that generates a rando number. If you want that number to be trully different seed srand to time...if you need more info about this, do a search on the board.
add the two rand numbers, get user input, and compare....based on the comparison result go further.
this should get you sarted.....another hint...when you are testing and debugging your program seed rand to a constant value.
//get random nuber here;
int number1 = get_rand();
int number2 = get_rand();
int sum = number1 + number2;
//main prog loop
while( guessing )
//get user input compare that to sum using if statement
//if TRUE display it and break out of the loop, if not continue