C++ Program to Calculate Power of a Number

C++ program to find the power of a number using loop

Source Code: 

#include <iostream>
using namespace std;
int main() 
{
    int exponent;
    float base, result = 1;
    cout << "Enter base and exponent respectively:  ";
    cin >> base >> exponent;
    cout << base << "^" << exponent << " = ";
    while (exponent != 0) {
        result *= base;
        --exponent;
    }
    cout << result;
    
    return 0;
}

Enter base and exponent respectively: 3.4 5
3.4^5 = 454.354

Finding power of a number in C++: 
Here, we are going to learn how to find the power of a number using loop in C++?

Here, we are going to calculate the value of Nth power of a number without using pow function.

The idea is using loop. We will be multiplying a number (initially with value 1) by the number input by user (of which we have to find the value of Nth power) for N times. For multiplying it by N times, we need to run our loop N times. Since we know the number of times loop will execute, so we are using for loop.

Power of a Number Using Non-Recursive C++ Program

The program to find the power of a number using a non-recursive program is given as follows −

Example

#include<iostream>
using namespace std;
int power(int x, int y) {  
   int i,power=1;
   if(y == 0)
      return 1;
   for(i=1;i<=y;i++)
      power=power*x;
   return power;
} 
int main() { 
   int x = 3; 
   int y = 4; 
   cout<<"x = "<<x<<endl;;
   cout<<"y = "<<y<<endl;
   cout<<"x^y = "<<power(x,y);
   return 0; 
} 

x = 3
y = 4
x^y = 81

In the above program, the function power() is used to calculate the power of a number. It is a non-recursive function. In the function, a for loop is used which runs from 1 to y. For each iteration of the loop, x is multiplied with power.

So, x is multiplied with itself y times and the result is stored in power. This leads to x^y being stored in power. Then power is returned to the main() function.

The following code snippet demonstrates this −

int power(int x, int y) {  
   int i, power = 1;
   if(y==0)
      return 1;
   for(i=1;i<=y;i++)
      power = power*x;
   return power;
} 

In main(), the values of x, y and x^y are displayed. This is shown in the code snippet given below −

cout<<"x = "<<x<<endl;;
cout<<"y = "<<y<<endl;
cout<<"x^y = "<<power(x,y);

Power of a Number Using Recursive Program

The program to find the power of a number using a recursive program is given as follows.

Example

#include<iostream>
using namespace std;
int power(int x, int y) {  
   if (y == 0) 
      return 1; 
   else if (y%2 == 0) 
      return power(x, y/2)*power(x, y/2); 
   else
      return x*power(x, y/2)*power(x, y/2);
} 
int main() { 
   int x = 3; 
   int y = 4; 
   cout<<"x = "<<x<<endl;;
   cout<<"y = "<<y<<endl;
   cout<<"x^y = "<<power(x,y);
   return 0; 
} 

Output

x = 3
y = 4
x^y = 81

In the above program, power() is a recursive function. If the value of y is 0, it returns 1. If y is even, it recursively calls itself with the values x and y/2 and returns power(x, y/2)*power(x, y/2). If y is odd, it recursively calls itself with the values x and y/2 and returns x*power(x, y/2)*power(x, y/2). This is demonstrated by the following code snippet.

int power(int x, int y) {  
   if (y == 0) 
      return 1; 
   else if (y%2 == 0) 
      return power(x, y/2)*power(x, y/2); 
   else
      return x*power(x, y/2)*power(x, y/2);    
} 

In main(), the values of x, y and x^y are displayed. This is shown in the code snippet given below.