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📜  无需使用乘法(*)和除法(/)运算符即可编写自己的Power

📅  最后修改于: 2021-04-30 03:32:49             🧑  作者: Mango

方法1(使用嵌套循环)
我们可以通过使用重复加法来计算功效。
例如计算5 ^ 6。
1)前5次加5,我们得到25。(5 ^ 2)
2)然后5乘以25,得到125。(5 ^ 3)
3)然后5次加125,我们得到625(5 ^ 4)
4)然后5次加625,我们得到3125(5 ^ 5)
5)然后5次加3125,我们得到15625(5 ^ 6)

C++
// C++ code for power function
#include 
using namespace std;
 
/* Works only if a >= 0 and b >= 0 */
int pow(int a, int b)
{
    if (b == 0)
        return 1;
    int answer = a;
    int increment = a;
    int i, j;
    for(i = 1; i < b; i++)
    {
        for(j = 1; j < a; j++)
        {
            answer += increment;
        }
        increment = answer;
    }
    return answer;
}
 
// Driver Code
int main()
{
    cout << pow(5, 3);
    return 0;
}
 
// This code is contributed
// by rathbhupendra


C
#include
/* Works only if a >= 0 and b >= 0  */
int pow(int a, int b)
{
  //base case : anything raised to the power 0 is 1
  if (b == 0)
    return 1;
  int answer = a;
  int increment = a;
  int i, j;
  for(i = 1; i < b; i++)
  {
     for(j = 1; j < a; j++)
     {
        answer += increment;
     }
     increment = answer;
  }
  return answer;
}
 
/* driver program to test above function */
int main()
{
  printf("\n %d", pow(5, 3));
  getchar();
  return 0;
}


Java
import java.io.*;
 
class GFG {
     
    /* Works only if a >= 0 and b >= 0 */
    static int pow(int a, int b)
    {
        if (b == 0)
            return 1;
             
        int answer = a;
        int increment = a;
        int i, j;
         
        for (i = 1; i < b; i++) {
            for (j = 1; j < a; j++) {
                answer += increment;
            }
            increment = answer;
        }
         
        return answer;
    }
 
    // driver program to test above function
    public static void main(String[] args)
    {
        System.out.println(pow(5, 3));
    }
}
 
// This code is contributed by vt_m.


Python
# Python 3 code for power
# function
 
# Works only if a >= 0 and b >= 0
def pow(a,b):
    if(b==0):
        return 1
         
    answer=a
    increment=a
     
    for i in range(1,b):
        for j in range (1,a):
            answer+=increment
        increment=answer
    return answer
 
# driver code
print(pow(5,3))
 
# this code is contributed
# by Sam007


C#
using System;
 
class GFG
{
    /* Works only if a >= 0 and b >= 0 */
    static int pow(int a, int b)
    {
        if (b == 0)
            return 1;
             
        int answer = a;
        int increment = a;
        int i, j;
         
        for (i = 1; i < b; i++) {
            for (j = 1; j < a; j++) {
                answer += increment;
            }
            increment = answer;
        }
         
        return answer;
    }
 
    // driver program to test
    // above function
    public static void Main()
    {
        Console.Write(pow(5, 3));
    }
}
 
// This code is contributed by Sam007


PHP
= 0
// and b >= 0
function poww($a, $b)
{
    if ($b == 0)
        return 1;
    $answer = $a;
    $increment = $a;
    $i;
    $j;
    for($i = 1; $i < $b; $i++)
    {
        for($j = 1; $j < $a; $j++)
        {
            $answer += $increment;
        }
        $increment = $answer;
    }
    return $answer;
}
 
    // Driver Code
    echo( poww(5, 3));
  
// This code is contributed by nitin mittal.
?>


Javascript


C++
#include
using namespace std;
 
/* A recursive function to get x*y */
int multiply(int x, int y)
{
    if(y)
        return (x + multiply(x, y - 1));
    else
        return 0;
}
 
/* A recursive function to get a^b
Works only if a >= 0 and b >= 0 */
int pow(int a, int b)
{
    if(b)
        return multiply(a, pow(a, b - 1));
    else
        return 1;
}
 
// Driver Code
int main()
{
    cout << pow(5, 3);
    getchar();
    return 0;
}
 
// This code is contributed
// by Akanksha Rai


C
#include
/* A recursive function to get a^b
  Works only if a >= 0 and b >= 0  */
int pow(int a, int b)
{
   if(b)
     return multiply(a, pow(a, b-1));
   else
    return 1;
}   
 
/* A recursive function to get x*y */
int multiply(int x, int y)
{
   if(y)
     return (x + multiply(x, y-1));
   else
     return 0;
}
 
/* driver program to test above functions */
int main()
{
  printf("\n %d", pow(5, 3));
  getchar();
  return 0;
}


Java
import java.io.*;
 
class GFG {
     
    /* A recursive function to get a^b
    Works only if a >= 0 and b >= 0 */
    static int pow(int a, int b)
    {
         
        if (b > 0)
            return multiply(a, pow(a, b - 1));
        else
            return 1;
    }
 
    /* A recursive function to get x*y */
    static int multiply(int x, int y)
    {
         
        if (y > 0)
            return (x + multiply(x, y - 1));
        else
            return 0;
    }
 
    /* driver program to test above functions */
    public static void main(String[] args)
    {
        System.out.println(pow(5, 3));
    }
}
 
// This code is contributed by vt_m.


Python3
def pow(a,b):
     
    if(b):
        return multiply(a, pow(a, b-1));
    else:
        return 1;
      
# A recursive function to get x*y *
def multiply(x, y):
     
    if (y):
        return (x + multiply(x, y-1));
    else:
        return 0;
 
# driver program to test above functions *
print(pow(5, 3));
 
 
# This code is contributed
# by Sam007


C#
using System;
 
class GFG
{
    /* A recursive function to get a^b
    Works only if a >= 0 and b >= 0 */
    static int pow(int a, int b)
    {
         
        if (b > 0)
            return multiply(a, pow(a, b - 1));
        else
            return 1;
    }
 
    /* A recursive function to get x*y */
    static int multiply(int x, int y)
    {
         
        if (y > 0)
            return (x + multiply(x, y - 1));
        else
            return 0;
    }
 
    /* driver program to test above functions */
    public static void Main()
    {
        Console.Write(pow(5, 3));
    }
}
 
// This code is contributed by Sam007


PHP
= 0 and b >= 0 */
function p_ow( $a, $b)
{
    if($b)
        return multiply($a,
          p_ow($a, $b - 1));
    else
        return 1;
}
 
/* A recursive function
   to get x*y */
function multiply($x, $y)
{
    if($y)
        return ($x + multiply($x, $y - 1));
    else
        return 0;
}
 
// Driver Code
echo pow(5, 3);
 
// This code is contributed by anuj_67.
?>


Javascript


输出 :

125

方法2(使用递归)
递归添加a以获得两个数字的乘法。并递归乘法加薪到电力B。

C++

#include
using namespace std;
 
/* A recursive function to get x*y */
int multiply(int x, int y)
{
    if(y)
        return (x + multiply(x, y - 1));
    else
        return 0;
}
 
/* A recursive function to get a^b
Works only if a >= 0 and b >= 0 */
int pow(int a, int b)
{
    if(b)
        return multiply(a, pow(a, b - 1));
    else
        return 1;
}
 
// Driver Code
int main()
{
    cout << pow(5, 3);
    getchar();
    return 0;
}
 
// This code is contributed
// by Akanksha Rai

C

#include
/* A recursive function to get a^b
  Works only if a >= 0 and b >= 0  */
int pow(int a, int b)
{
   if(b)
     return multiply(a, pow(a, b-1));
   else
    return 1;
}   
 
/* A recursive function to get x*y */
int multiply(int x, int y)
{
   if(y)
     return (x + multiply(x, y-1));
   else
     return 0;
}
 
/* driver program to test above functions */
int main()
{
  printf("\n %d", pow(5, 3));
  getchar();
  return 0;
}

Java

import java.io.*;
 
class GFG {
     
    /* A recursive function to get a^b
    Works only if a >= 0 and b >= 0 */
    static int pow(int a, int b)
    {
         
        if (b > 0)
            return multiply(a, pow(a, b - 1));
        else
            return 1;
    }
 
    /* A recursive function to get x*y */
    static int multiply(int x, int y)
    {
         
        if (y > 0)
            return (x + multiply(x, y - 1));
        else
            return 0;
    }
 
    /* driver program to test above functions */
    public static void main(String[] args)
    {
        System.out.println(pow(5, 3));
    }
}
 
// This code is contributed by vt_m.

Python3

def pow(a,b):
     
    if(b):
        return multiply(a, pow(a, b-1));
    else:
        return 1;
      
# A recursive function to get x*y *
def multiply(x, y):
     
    if (y):
        return (x + multiply(x, y-1));
    else:
        return 0;
 
# driver program to test above functions *
print(pow(5, 3));
 
 
# This code is contributed
# by Sam007

C#

using System;
 
class GFG
{
    /* A recursive function to get a^b
    Works only if a >= 0 and b >= 0 */
    static int pow(int a, int b)
    {
         
        if (b > 0)
            return multiply(a, pow(a, b - 1));
        else
            return 1;
    }
 
    /* A recursive function to get x*y */
    static int multiply(int x, int y)
    {
         
        if (y > 0)
            return (x + multiply(x, y - 1));
        else
            return 0;
    }
 
    /* driver program to test above functions */
    public static void Main()
    {
        Console.Write(pow(5, 3));
    }
}
 
// This code is contributed by Sam007

的PHP

= 0 and b >= 0 */
function p_ow( $a, $b)
{
    if($b)
        return multiply($a,
          p_ow($a, $b - 1));
    else
        return 1;
}
 
/* A recursive function
   to get x*y */
function multiply($x, $y)
{
    if($y)
        return ($x + multiply($x, $y - 1));
    else
        return 0;
}
 
// Driver Code
echo pow(5, 3);
 
// This code is contributed by anuj_67.
?>

Java脚本


输出 :

125