C++ Program - Power of a Number


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If power (or exponential) of number indicates how many the number is multiplied by itself to get the final number. For example:

$$x$$ raised to the power $$2$$ = $$x^2 = x*x$$

$$x$$ raised to the power $$3$$ = $$x^3 = x*x*x$$

Example: Using conditional statement

In the below example, a function called Power() is created to calculate power of a number. It uses while loop to achieve this. This method can be used to calculate the power of a number where power should be a non-negative integer.

#include <iostream>
using namespace std;

static void Power(double, int);

static void Power(double x, int n) {
  double finalnum = 1;
  int n1 = n;
  while(n1 > 0){
    finalnum = finalnum * x;
    n1--;
  }
  cout<<x<<" raised to the power "<<n<<" = "<<finalnum<<"\n";
}

int main() {
  Power(3, 5);
  Power(5, 0);
  Power(6, 2);
  return 0;
}

Output

3.0 raised to the power 5 = 243.0
5.0 raised to the power 0 = 1.0
6.0 raised to the power 2 = 36.0

Example: Using pow() function of C++ <cmath> header file

The pow() function of C++ <cmath> header file can also be used to calculate power of a number. It can be used to calculate $$x^n$$ for any value of n (n can be negative or fraction).

#include <iostream>
#include <cmath>
using namespace std;

int main() {
  double x = 3, y = 5, z = 6;
  double a = 5, b = 0, c = 2;

  double x1 = pow(x, 1/3.0);
  double y1 = pow(y, 1/3.0);
  cout<<x<<" raised to the power "<<a<<" = "<<pow(x, a)<<"\n";
  cout<<y<<" raised to the power "<<b<<" = "<<pow(y, b)<<"\n";
  cout<<z<<" raised to the power "<<c<<" = "<<pow(z, c)<<"\n";
  return 0;
}

Output

3.0 raised to the power 5.0 = 243.0
5.0 raised to the power 0.0 = 1.0
6.0 raised to the power 2.0 = 36.0

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