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Numbers
Mathematical

Find the distance between two points

java
double distance = Point2D.distance(x1, y1, x2, y2);
Point2D point1 = new Point2D.Double(x1, y1);
Point2D point2 = new Point2D.Double(x2, y2);
double distance = point1.distance(point2);
double distance = Math.hypot(x2-x1, y2-y1);
csharp
System.Drawing.Point p = new System.Drawing.Point(13, 14),
p1 = new System.Drawing.Point(10, 10);
double distance = Math.Sqrt(Math.Pow(p1.X - p.X, 2) + Math.Pow(p1.Y - p.Y, 2)));
cpp
Point p1 = {34, 78}, p2 = {67, -45};
double distance = ::distance(p1, p2);
Console::WriteLine("{0,3:F2}", distance);
erlang
Distance = distance({point, 34, 78}, {point, 67, -45}),
io:format("~.2f~n", [Distance]).
Distance = distance(point:new(34, 78), point:new(67, -45)),
io:format("~.2f~n", [Distance]).
fsharp
let distance' = distance (34, 78) (67, -45)
printfn "%3.2f" distance'
fantom
px1 := 34.0f; py1 := 78.0f; px2 := 67.0f; py2 := -45.0f
distance := |Float x1, Float y1, Float x2, Float y2 -> Float|
{ ((x2-x1).pow(2.0f) + (y2-y1).pow(2.0f)).sqrt }

distance(px1, py1, px2, py2)
groovy
distance = distance(x1, y1, x2, y2)
distance = sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1))
Output

Zero pad a number

Given the number 42, pad it to 8 characters like 00000042
java
String formatted = new DecimalFormat("00000000").format(42);
String formatted = String.format("%08d", 42);
csharp
string.Format("{0,8:D8}", 42);
cpp
String^ formatted = Convert::ToString(42)->PadLeft(8, '0');
String^ formatted = String::Format("{0,8:D8}", 42);
std::printf("%08d", 42);
std::ostringstream os;
os << std::setw(8) << std::setfill('0') << 42 << std::ends;
std::cout << os.str() << std::endl;
std::cout << boost::format("%|08|") % 42 << std::endl;
erlang
Formatted = io_lib:format("~8..0B", [42]),
io:format("~8..0B~n", [42]).
fsharp
printfn "%08d" 42
let formatted = sprintf "%08d" 42
printfn "%s" formatted
let buffer = new StringBuilder()
Printf.bprintf buffer "%08d" 42
printfn "%s" (buffer.ToString())
let formatted = String.Format("{0,8:D8}", 42)
Console.WriteLine(formatted)
let formatted = Convert.ToString(42).PadLeft(8, '0')
Console.WriteLine(formatted)
fantom
formatted := 42.toStr.padl(8, '0')
formatted := 42.toLocale("00000000")
groovy
formatted = new DecimalFormat('00000000').format(42)
formatted = 42.toString().padLeft(8, '0')
// to stdout
printf "%08d\n", 42
// to a string
formatted = sprintf("%08d", 42)
formatted = String.format("%08d", 42)

Right Space pad a number

Given the number 1024 right pad it to 6 characters "1024  "
java
private static String spaces(int spaces) {
StringBuffer sb = new StringBuffer();
for(int i=0; i<spaces; i++) {
sb.append(' ');
}
return sb.toString();
}

private static String rightPad(int number, int spaces) {
String numberString = String.valueOf(number);
return numberString + spaces(spaces - numberString.length());
}
String text = StringUtils.rightPad(String.valueOf(1024), 6)
String formatted = String.format("%-6d", 1024);
csharp
public class NumberRightPadding {
public static void Main() {
string withStringDotFormat = string.Format("{0,-6}", 1024);
string withToStringDotPadRight = 1024.ToString().PadRight(6);
}
}
cpp
String^ formatted = Convert::ToString(1024)->PadRight(6);
String^ formatted = String::Format("{0,-6:D}", 1024);
std::printf("%-6d\n", 1024);
std::ostringstream os;
os << std::setw(6) << std::setfill(' ') << std::left << 1024 << std::ends;
std::cout << os.str() << std::endl;
std::cout << boost::format("%|-6|") % 1024 << std::endl;
erlang
Formatted = io_lib:format("~-6B", [1024]),
io:format("~-6B~n", [1024]).
fsharp
printfn "%-6d" 1024
let formatted = String.Format("{0,-6:D}", 1024)
Console.WriteLine(formatted)
let formatted = Convert.ToString(1024).PadRight(6)
Console.WriteLine(formatted)
fantom
formatted := 1024.toStr.padr(6)
groovy
println 1024.toString().padRight(6)
formatted = sprintf("%-6d", 1024)

Format a decimal number

Format the number 7/8 as a decimal with 2 places: 0.88
java
String formatted = String.format("%3.2f", 7./8.);
csharp
public class FormatDecimal {
public static void Main() {
decimal result = decimal.Round( 7 / 8m, 2);
System.Console.WriteLine(result);
}
}
cpp
String^ formatted = String::Format("{0,3:F2}", result);
Console::WriteLine("{0,3:F2}", (7. / 8.));
std::printf("%3.2f\n", result);
std::ostringstream os;
os.width(3); os.fill('0'); os.setf(std::ios::fixed|std::ios::showpoint); os.precision(2);
os << result << std::ends;
std::cout << os.str() << std::endl;
std::cout << boost::format("%|3.2f|") % result << std::endl;
erlang
Formatted = io_lib:format("~.2f", [7/8]),
io:format("~.2f~n", [7/8]).
fsharp
printfn "%3.2f" (0.7 / 0.8)
let formatted = String.Format("{0,3:F2}", (0.7 / 0.8))
Console.WriteLine(formatted)
fantom
formatted := (7.0/8.0).toLocale("0.00")
groovy
def result = 7/8
println result.round(new MathContext(2))
def result = 7/8
printf "%.2g", result
new Double(7/8).round(2)

Left Space pad a number

Given the number 73 left pad it to 10 characters "        73"
java
private static String spaces(int spaces) {
StringBuffer sb = new StringBuffer();
for(int i=0; i<spaces; i++) {
sb.append(' ');
}
return sb.toString();
}

private static String leftPad(int number, int spaces) {
String numberString = String.valueOf(number);
return spaces(spaces - numberString.length()) + numberString;
}
String formatted = String.format("%10d", 73);
csharp
public class NumberLeftPadding {
public static void Main() {
string withStringDotFormat = string.Format("{0,10}", 73);
string withToStringDotPadLeft = 73.ToString().PadLeft(10);
}
}
cpp
String^ formatted = Convert::ToString(73)->PadLeft(10);
String^ formatted = String::Format("{0,10:D}", 73);
std::printf("%10d\n", 73);
std::ostringstream os;
os << std::setw(10) << std::setfill(' ') << 73 << std::ends;
std::cout << os.str() << std::endl;
std::cout << boost::format("%|10|") % 73 << std::endl;
erlang
Formatted = io_lib:format("~10B", [73]),
io:format("~10B~n", [73]).
fsharp
let formatted = sprintf "%10d" 73
printfn "%s" formatted
let formatted = String.Format("{0,10:D}", 73)
Console.WriteLine(formatted)
let formatted = Convert.ToString(73).PadLeft(10)
Console.WriteLine(formatted)
fantom
formatted := 73.toStr.padl(10)
groovy
println 73.toString().padLeft(10)
printf "%10d\n", 73
Random

Generate a random integer in a given range

Produce a random integer between 100 and 200 inclusive
java
Random random = new Random();
int randomInt = random.nextInt(200-100+1)+100;
csharp
System.Random r = new System.Random();
int random = r.Next(100,201);
cpp
Random^ rnd = gcnew Random;
int rndInt = rnd->Next(100, 201);
std::srand(std::time(NULL));

unsigned lb = 100, ub = 200;
unsigned rnd = lb + (rand() % ((ub - lb) + 1));
typedef boost::uniform_int<> Distribution;
typedef boost::mt19937 RNG;

Distribution distribution(100, 200);
RNG rng; rng.seed(std::time(NULL));
boost::variate_generator<RNG&, Distribution> generator(rng, distribution);

unsigned rnd = generator();
erlang
RandomInt = gen_rand_integer(100, 200),
fsharp
let rnd = new Random()
let rndInt = rnd.Next(100, 201)
fantom
r := Int.random(100..200)
groovy
random = new Random()
randomInt = random.nextInt(200-100+1)+100

Generate a repeatable random number sequence

Initialise a random number generator with a seed and generate five decimal values. Reset the seed and produce the same values.
java
int[] arr1 = genFillRand(new int[5], new Random(12345), 100, 200);
int[] arr2 = genFillRand(new int[5], new Random(12345), 100, 200);

for (int[] arr : new int[][]{ arr1, arr2 }) { for (int i : arr) System.out.printf("%d ", i); System.out.println(); }
csharp
using System;

public class RepeatableRandom {
public static void Main() {
var r = new Random(12); // seed is 12

for (int i = 0; i < 5; i++)
Console.WriteLine(r.Next());

r = new Random(12);

for (int i = 0; i < 5; i++)
Console.WriteLine(r.Next());
}
}

cpp
void printAction(int i) { Console::Write("{0} ", i); }

array<int>^ genFillRand(array<int>^ arr, Random^ rnd, int lb, int ub)
{
for (int i = 0; i < arr->Length; ++i) arr[i] = rnd->Next(lb, ub + 1); return arr;
}

int main()
{
array<int>^ arr1 = genFillRand(gcnew array<int>(5), gcnew Random(12345), 100, 200);
array<int>^ arr2 = genFillRand(gcnew array<int>(5), gcnew Random(12345), 100, 200);

Action<int>^ print = gcnew Action<int>(printAction);
Array::ForEach<int>(arr1, print); Console::WriteLine();
Array::ForEach<int>(arr2, print); Console::WriteLine();
}
typedef boost::uniform_int<> Distribution;
typedef boost::mt19937 RNG;

Distribution distribution(100, 200);
RNG rng;
boost::variate_generator<RNG&, Distribution> generator(rng, distribution);

rng.seed(42L);
std::generate_n(std::ostream_iterator<unsigned>(std::cout, " "), 5, generator);

rng.seed(42L);
std::cout << std::endl;
std::generate_n(std::ostream_iterator<unsigned>(std::cout, " "), 5, generator);
erlang
setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]),

setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]).
fsharp
let (seed, lb, ub) = (12345, 100, 200)

let mutable rnd = new Random(seed)
for i = 1 to 5 do printf "%d " (rnd.Next(lb, ub + 1)) done ; printfn ""

rnd <- new Random(seed)
for i = 1 to 5 do printf "%d " (rnd.Next(lb, ub + 1)) done ; printfn ""
fantom
rand := Random.makeSeeded(12345)
first := Int[,].fill(0,5).map { rand.next(100..200) }

rand2 := Random.makeSeeded(12345)
second := Int[,].fill(0,5).map { rand2.next(100..200) }
groovy
random = new Random(12345)
orig = (1..5).collect { random.nextInt(200-100+1)+100 }
random = new Random(12345)
repeat = (1..5).collect { random.nextInt(200-100+1)+100 }
assert orig == repeat