Efficient solution to power calculation of C language _c language

Source: Internet
Author: User

This paper demonstrates the efficient solution of power calculation in C language. is of practical value. Share to everyone for your reference. The specific methods are as follows:

The topics are as follows:

Given base, the power exp of base is obtained

Only consider the basic functions, do not make any boundary conditions of the decision, you can get the following code:

#include <iostream>

using namespace std;

int cacexp (int base, int exp)
{
 int result = 1;
 int thebase = 1;
 while (exp)
 {
 if (exp & 0x01) Result
  = result * BASE;
 Base = base * BASE;
 EXP = exp >> 1;
 }
 
 return result;
}

int getrecurexp (int base, int exp)
{
 if (exp = = 0)
 {return
 1;
 }

 if (exp = = 1)
 {return
 base;
 }

 int result = Getrecurexp (base, exp >> 1);
 Result *= result;
 IF (exp & 0x01) result
 *= base;

 return result;
}

int main ()
{
 for (int i = 1; i < i++)
 {int result
 = Cacexp (2, i);
 int result = Getrecurexp (2, i);
 cout << "Result:" << result << Endl;
 }

 return 0;
}

Then look at the numerical integer method of solving the number of times:

#include <iostream> using namespace std;
 BOOL Equalzero (double) {if (number < 0.000001 && number > -0.000001) return true;
else return false;
 Double _mypow (double base, int exp) {if (exp = 0) return 1;

 if (exp = = 1) return base;
 Double result = _mypow (base, exp >> 1);
 Result *= result;

 IF (exp & 0x01) result *= base;
return result;
 
 Double _mypow2 (double base, int exp) {if (exp = 0) return 1;
 double result = 1;
 while (exp) {if (exp & 0x01) result *= base;
 Base *= Base;
 EXP = exp >> 1;
return result;
 Double Mypow (double base, int exp) {if (Equalzero (base)) return 0;

 if (exp = = 0) return 1;
 BOOL flag = FALSE;
 if (exp < 0) {flag = true;
 exp =-exp;
 Double result = _mypow2 (base, exp);
 if (flag) {result = 1/result;
return result;
 } void Main () {double base = 2.0;

 int exp =-5;
 Double result = MYPOW (base, exp); cout << "Result:" << result << Endl

 }

I believe that this article on the C program algorithm design learning has a certain reference value.

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