程序计算除法小数点后n位

给定3个数字，x，y和n可计算除法(x / y)，最多可保留n个小数位。
例子 ：

Input  : x = 22, y = 7, n = 10
Output : 3.1428571428
Explanation :
Since n = 10, division (x / y) is taken till
10 decimal places.

Input  : x = 22, y = 7, n = 20
Output : 3.14285714285714285714

方法 ：

1. 得到余数，然后将其除以除数，再乘以十，然后进行下一个迭代。
2. 如果达到完整的结果，则可能不需要继续操作，直到达到预定义的迭代次数。

C++

// CPP program to compute division upto n
// decimal places.
#include 
using namespace std;
 
void precisionCompute(int x, int y, int n)
{
    // Base cases
    if (y == 0) {
        cout << "Infinite" << endl;
        return;
    }
    if (x == 0) {
        cout << 0 << endl;
        return;
    }
    if (n <= 0) {
        // Since n <= 0, don't compute after
        // the decimal
        cout << x / y << endl;
        return;
    }
 
    // Handling negative numbers
    if (((x > 0) && (y < 0)) || ((x < 0) && (y > 0))) {
        cout << "-";
        x = x > 0 ? x : -x;
        y = y > 0 ? y : -y;
    }
 
    // Integral division
    int d = x / y;
 
    // Now one by print digits after dot
    // using school division method.
    for (int i = 0; i <= n; i++) {
        cout << d;
        x = x - (y * d);
        if (x == 0)
            break;
        x = x * 10;
        d = x / y;
        if (i == 0)
            cout << ".";
    }
}
 
// Driver Program
int main()
{
    int x = 22, y = 7, n = 15;
    precisionCompute(x, y, n);
    return 0;
}

Java

// Java program to compute division upto n
// decimal places.
import java.util.*;
 
class Eulerian {
    public static void precisionCompute(int x, int y, int n)
    {
        // Base cases
        if (y == 0) {
            System.out.print("Infinite");
            return;
        }
        if (x == 0) {
            System.out.print("0");
            return;
        }
        if (n <= 0) {
            // Since n <= 0, don't compute after
            // the decimal
            System.out.print(x / y);
            return;
        }
 
        // Handling negative numbers
        if (((x > 0) && (y < 0)) || ((x < 0) && (y > 0))) {
            System.out.print("-");
            x = x > 0 ? x : -x;
            y = y > 0 ? y : -y;
        }
 
        // Integral division
        int d = x / y;
 
        // Now one by print digits after dot
        // using school division method.
        for (int i = 0; i <= n; i++) {
            System.out.print(d);
            x = x - (y * d);
            if (x == 0)
                break;
            x = x * 10;
            d = x / y;
            if (i == 0)
                System.out.print(".");
        }
    }
 
    public static void main(String[] args)
    {
        int x = 22, y = 7, n = 15;
        precisionCompute(x, y, n);
    }
}
 
// This code is contributed by rishabh_jain

C#

// C# program to compute division
// upto n decimal places.
using System;
 
class Eulerian {
 
    public static void precisionCompute(int x, int y,
                                        int n)
    {
        // Base cases
        if (y == 0) {
            Console.WriteLine("Infinite");
            return;
        }
        if (x == 0) {
            Console.WriteLine("0");
            return;
        }
        if (n <= 0) {
 
            // Since n <= 0, don't compute after
            // the decimal
            Console.WriteLine(x / y);
            return;
        }
 
        // Handling negative numbers
        if (((x > 0) && (y < 0)) || ((x < 0) && (y > 0))) {
            Console.WriteLine("-");
            x = x > 0 ? x : -x;
            y = y > 0 ? y : -y;
        }
 
        // Integral division
        int d = x / y;
 
        // Now one by print digits after dot
        // using school division method.
        for (int i = 0; i <= n; i++) {
            Console.Write(d);
            x = x - (y * d);
            if (x == 0)
                break;
            x = x * 10;
            d = x / y;
            if (i == 0)
                Console.Write(".");
        }
    }
 
    // Driver code
    public static void Main()
    {
        int x = 22, y = 7, n = 15;
        precisionCompute(x, y, n);
    }
}
 
// This code is contributed by vt_m

PHP

 0) && ($y < 0)) ||
        (($x < 0) && ($y > 0)))
    {
        echo "-";
        $x = $x > 0 ? $x : -$x;
        $y = $y > 0 ? $y : -$y;
    }
 
    // Integral division
    $d = $x / $y;
 
    // Now one by print digits after dot
    // using school division method.
    for ($i = 0; $i <= $n; $i++)
    {
        echo $d;
        $x = $x - ($y * $d);
        if ($x == 0)
            break;
        $x = $x * 10;
        $d = $x / $y;
        if ($i == 0)
            echo ".";
    }
}
 
// Driver Code
$x = 22; $y = 7; $n = 15;
 
precisionCompute($x, $y, $n);
 
// This code is contributed by aj_36
?>

Python3

# Python3 program to compute
# division upto n decimal places.
 
def precisionCompute(x, y, n):
     
    # Base cases
    if y == 0:
        print("Infinite");
        return;
    if x == 0:
        print(0);
        return;
    if n <= 0:
         
        # Since n <= 0, don't
        # compute after the decimal
        print(x / y);
        return;
         
    # Handling negative numbers
    if (((x > 0) and (y < 0)) or
        ((x < 0) and (y > 0))):
        print("-", end = "");
        if x < 0:
            x = -x;
        if y < 0:
            y = -y;
             
    # Integral division
    d = x / y;
     
    # Now one by print digits
    # after dot using school
    # division method.
    for i in range(0, n + 1):
        print(d);
        x = x - (y * d);
        if x == 0:
            break;
        x = x * 10;
        d = x / y;
        if (i == 0):
            print(".", end = "");
 
# Driver Code
x = 22;
y = 7;
n = 15;
precisionCompute(x, y, n);
 
# This code is contributed by mits

Javascript

 
// JavaScript program to compute division upto n
// decimal places.
 
    function precisionCompute(x, y, n)
    {
        // Base cases
        if (y == 0) {
            document.write("Infinite");
            return;
        }
        if (x == 0) {
            document.write("0");
            return;
        }
        if (n <= 0) {
            // Since n <= 0, don't compute after
            // the decimal
            document.write(x / y);
            return;
        }
   
        // Handling negative numbers
        if (((x > 0) && (y < 0)) || ((x < 0) && (y > 0))) {
            document.write("-");
            x = x > 0 ? x : -x;
            y = y > 0 ? y : -y;
        }
   
        // Integral division
        let d = x / y;
   
        // Now one by print digits after dot
        // using school division method.
        for (let i = 0; i <= n; i++) {
            document.write(d);
            x = x - (y * d);
            if (x == 0)
                break;
            x = x * 10;
            d = x / y;
            if (i == 0)
                document.write(".");
        }
    }
 
// Driver code
         
        let x = 22, y = 7, n = 15;
        precisionCompute(x, y, n);
                   

输出 ：

3.142857142857142