picat/fib.pi



aa208e4 ^


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main =>
S = 0,
    I = 1,
    F = fib(I),
    while (F <= 4000000)
        if (F mod 2 == 0) then
            S := S+F
        end,
        I := I+1,
        F := fib(I)
    end,
    printf("Sum of the even-valued terms is %w%n",S).
main([A1]) =>
    printf("fib(%s)=%w%n",A1,A1.to_integer().fib()).
table
fib(1) = 1.
fib(2) = 2.
fib(N) = fib(N-1)+fib(N-2).