How to input the middle power in c++

C Input of power can be done through the following methods: use the pow(base, exponent) function to directly input the power expression. Use math libraries such as exp and log in the <cmath> header file to perform operations. When the exponent is an integer, it can be calculated efficiently through bit operations.

Input of the power of C

In C, use the pow(base, exponent) function to calculate a The power of a number, where base is the base and exponent is the exponent.

Directly input a power expression

The most direct way to input a power expression is to use the pow function:

<code class="cpp">#include <cmath>

int main() {
  double result = pow(2.0, 3.0); // 计算 2 的三次方
  std::cout << "结果：" << result << std::endl;
  return 0;
}</code>

Using the math library

Additional options are provided in the <cmath> header file of the C standard library:

• exp: Calculate the exponent of e
• log: Calculate the natural logarithm
• sqrt: Calculate the square root

For example, the following code uses the exp and log functions to calculate 2 raised to the third power:

<code class="cpp">#include <cmath>

int main() {
  double result = exp(3.0 * log(2.0)); // e^(3*ln(2)) 等于 2^3
  std::cout << "结果：" << result << std::endl;
  return 0;
}</code>

Using bitwise operations

When the exponent is an integer, bit operations can be used for more efficient calculations:

<code class="cpp">int power(int base, int exponent) {
  if (exponent == 0) return 1;
  if (exponent == 1) return base;
  if (exponent < 0) return 1 / power(base, -exponent);

  int result = 1;
  while (exponent > 0) {
    if (exponent % 2 == 1) result *= base;
    base *= base;
    exponent /= 2;
  }
  return result;
}

int main() {
  int result = power(2, 3); // 计算 2 的 3 次方
  std::cout << "结果：" << result << std::endl;
  return 0;
}</code>

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