Number

Check if a value is a number

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (number? <value>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

value	output
#f	B
’()	B
0	A
42	A
-2045	A

Check a number trait

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (<predicate> <value>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

predicate	value	output
zero?	0	A
zero?	1	B
positive?	42	A
positive?	-42	B
negative?	-42	A
negative?	42	B
even?	2	A
even?	3	B
odd?	3	A
odd?	2	B

Check a number class of integers

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (<predicate> <value>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

predicate	value	output
number?	0	A
number?	1	A
number?	-42	A
complex?	0	A
complex?	1	A
complex?	-42	A
real?	0	A
real?	1	A
real?	-42	A
rational?	0	A
rational?	1	A
rational?	-42	A
integer?	0	A
integer?	1	A
integer?	-42	A

Check a number class of non-numbers

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (<predicate> #f) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “B”.

Examples

predicate
number?
complex?
real?
rational?
integer?

Use literals

Given a file named “main.scm” with:

(import (scheme base))

(define x <value>)

When I successfully run stak main.scm

Then the exit status should be 0.

Examples

value
0
1
42
-1
-42

Use a negative integer

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (+ 66 -1))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Use large (but not big) integers

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (- 1065 1000))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Use integers around the encoding base

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (- <value> 60))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

value	output
127	C
128	D
129	E

Use arithmetic operators

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= <expression> <value>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

expression	value
(+)	0
(+ 1)	1
(+ 1 2)	3
(- 1)	-1
(- 0 1)	-1
(- 0 1 2)	-3
(*)	1
(* 2)	2
(* 2 3)	6
(/ 6 2)	3
(/ 6 2 3)	1

Use division operators

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= <expression> <value>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

expression	value
(quotient 6 2)	3
(quotient 6 3)	2
(quotient -6 2)	-3
(quotient -6 -2)	3
(truncate-quotient 6 2)	3
(truncate-quotient 6 3)	2
(truncate-quotient -6 2)	-3
(truncate-quotient -6 -2)	3
(remainder 8 3)	2
(remainder 8 -3)	2
(remainder -8 3)	-2
(remainder -8 -3)	-2
(truncate-remainder 8 3)	2
(truncate-remainder 8 -3)	2
(truncate-remainder -8 3)	-2
(truncate-remainder -8 -3)	-2
(modulo 5 1)	0
(modulo 5 2)	1
(modulo 8 3)	2
(modulo 8 -3)	-1
(modulo -8 3)	1
(modulo -8 -3)	-2
(floor-quotient 5 1)	5
(floor-quotient 5 2)	2
(floor-quotient 5 3)	1
(floor-quotient -5 2)	-3
(floor-quotient -5 -2)	2
(floor-remainder 5 1)	0
(floor-remainder 5 2)	1
(floor-remainder 5 3)	2
(floor-remainder -5 2)	1
(floor-remainder -5 -2)	-1
(floor-remainder 6 2)	0
(floor-remainder 6 -2)	0
(floor-remainder -6 2)	0
(floor-remainder -6 -2)	0

Use multi-value division operators

Given a file named “main.scm” with:

(import (scheme base))

(define-values (x y) <expression>)

(write-u8 (if (= x <quotient>) 65 66))
(write-u8 (if (= y <remainder>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “AA”.

Examples

expression	quotient	remainder
(floor/ 8 3)	2	2
(floor/ 8 -3)	-3	-1
(floor/ -8 3)	-3	1
(floor/ -8 -3)	2	-2
(truncate/ 8 3)	2	2
(truncate/ 8 -3)	-2	2
(truncate/ -8 3)	-2	-2
(truncate/ -8 -3)	2	-2

Calculate a multiplicative inverse

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (/ 2) (/ 1 2)) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Calculate a square

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (square <value>) <result>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

value	result
-3	9
-2	4
-1	1
0	0
1	1
2	4
3	9

Calculate a square root of an exact integer

Given a file named “main.scm” with:

(import (scheme base))

(define-values (x y) (exact-integer-sqrt <value>))

(write-u8 (if (= x <root>) 65 66))
(write-u8 (if (= y <remainder>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “AA”.

Examples

value	root	remainder
0	0	0
1	1	0
4	2	0
5	2	1
8	2	4
9	3	0

Calculate the greatest common divisor

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (gcd <x> <y>) <z>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

x	y	z
0	0	0
1	1	1
6	2	2
2	6	2
6	3	3
3	6	3
30	42	6
42	30	6
-30	42	6
-30	-42	6

Calculate the least common multiple

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (lcm <x> <y>) <z>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

x	y	z
1	1	1
2	3	6
3	2	6
6	10	30
10	6	30
-6	10	30
-6	-10	30

Calculate a numerator

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (numerator 42) 42) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Calculate a denominator

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (denominator 42) 1) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Compare numbers

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if <expression> 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

expression
(< 0 1)
(< 0 1 2)
(> 1 0)
(<= 0 1)
(<= 0 0)
(>= 1 0)
(>= 0 0)

Compare numbers with an insufficient number of arguments

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (< <values>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

values
0

Calculate a minimum

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (min <values>) <output>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

values	output
0	0
1	1
1 2	1
1 2 3	1
2 3 1	1
3 1 2	1

Calculate a maximum

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (max <values>) <output>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

values	output
0	0
1	1
1 2	2
1 2 3	3
2 3 1	3
3 1 2	3

Convert a number to a string

Given a file named “main.scm” with:

(import (scheme base))

(write-string (number->string <value> <radix>))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

value	radix	output
0		0
1		1
2		2
42		42
-1		-1
-2		-2
-42		-42
0	16	0
1	16	1
2	16	2
15	16	f
42	16	2a
-1	16	-1
-2	16	-2
-42	16	-2a
0	32	0
1	32	1
2	32	2
31	32	v
42	32	1a
-1	32	-1
-2	32	-2
-42	32	-1a

Convert a string to a number

Given a file named “main.scm” with:

(import (scheme base))

(write-string (number->string (string->number "<value>" <radix>)))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

value	radix	output
0		0
1		1
2		2
42		42
-1		-1
-2		-2
-42		-42
0	16	0
1	16	1
2	16	2
f	16	15
2a	16	42
2A	16	42
-1	16	-1
-2	16	-2
-2a	16	-42
-2A	16	-42
0	32	0
1	32	1
2	32	2
v	32	31
1a	32	42
1A	32	42
-1	32	-1
-2	32	-2
-1a	32	-42
-1A	32	-42

Convert an invalid string to a number

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (string->number "<value>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “B”.

Examples

value
x
foo
-
2x
-x
-2x