Give me a Ballpark

Problem

Calculate the arithmetic mean of a bunch of numbers.

23. Give me a ballpark, Comet 64

Solution 1

We assume that each of the registers int and reg is initially set to zero. Read a number from input and keep track of the cumulative sum. We also keep track of how many numbers we have read so far. If there are no more input values, calculate and print the average.

int++;                // How many numbers read so far.
reg = reg + input;    // The cumulative sum.
check input = null;   // Any more numbers?
jump if true: print;  // If not, go to "print".
jump to: end;         // Otherwise, go to "end".
print:                // The "print" branch.
    reg = reg / int;  // The arithmetic mean.
    output = reg;     // Print the average.
end:                  // End of program.

Solution 2

Similar to Solution 1, but we use an explicit loop. We remove a jump instruction and a label. This solution is optimal, according to the game.

loop:                     // Start of "loop".
    int++;                // How many numbers read so far.
    reg = reg + input;    // The cumulative sum.
    check input = null;   // Any more numbers?
    jump if false: loop;  // If yes, go to "loop".
reg = reg / int;          // The arithmetic mean.
output = reg;             // Print the average.