Implement exponentiation operation in C language

Code implementation of exponentiation operation in C language

In C language, it is not difficult to implement exponentiation operation (that is, finding the power of a number). There are usually two ways to implement exponentiation operations, namely loop calculation and recursive calculation. The code implementation of these two methods will be introduced below.

Method 1: Loop calculation

Loop calculation of powers can be achieved by repeatedly multiplying the base. The specific steps are as follows:

1. First define a function that receives two parameters x and n, representing the base and exponent respectively. The function returns a numeric result. The function prototype is as follows:

double power(double x, int n);

2. Create a variable result inside the function body to store the result of the exponentiation. Initialize result to 1, because any number raised to the 0th power is 1.
3. Judge the value of the index n. If n is greater than 0, enter the loop calculation stage; if n is less than 0, take the reciprocal of the base x, take the absolute value of the index n, and enter the loop calculation stage; if n is equal to 0, the result 1 is returned directly.
4. In the loop, each iteration multiplies the result by the base x, and the number of iterations is the absolute value of the index n. After the iteration is complete, result is returned as the result.

The following is a code example for looping to calculate powers:

#include <stdio.h>

double power(double x, int n)
{
    double result = 1.0;
    
    if (n > 0)
    {
        for (int i = 0; i < n; i++)
        {
            result *= x;
        }
    }
    else if (n < 0)
    {
        for (int i = 0; i < -n; i++)
        {
            result *= 1 / x;
        }
    }
    
    return result;
}

int main()
{
    double x = 2.0;
    int n = 3;
    double result = power(x, n);
    
    printf("%.2f的%d次幂为%.2f
", x, n, result);
    
    return 0;
}

In the above code, we define a power function to calculate powers, and then call the power function in the main function carry out testing. The running result will output 2.00 raised to the third power as 8.00.

Method 2: Recursive calculation

The idea of ​​recursively calculating exponentiation is to reduce the exponent n again and again and call the exponentiation function recursively. The specific steps are as follows:

1. Define a recursive function that receives two parameters x and n, representing the base and exponent respectively. The function returns a numeric result. The function prototype is as follows:

double power(double x, int n);

2. Determine the value of the exponent n inside the function. If n is greater than 0, multiply the base x by the recursive call power function power(x, n-1) The result of is used as the return value; if n is less than 0, take the reciprocal of the base Return result 1.

The following is a code example for recursively calculating powers:

#include <stdio.h>

double power(double x, int n)
{
    if (n > 0)
    {
        return x * power(x, n-1);
    }
    else if (n < 0)
    {
        return 1 / (x * power(x, -n-1));
    }
    else
    {
        return 1;
    }
}

int main()
{
    double x = 2.0;
    int n = 3;
    double result = power(x, n);
    
    printf("%.2f的%d次幂为%.2f
", x, n, result);
    
    return 0;
}

Also in the above code, we define a power function to calculate powers, and then call power in the main function function to test. The running result will output 2.00 raised to the third power as 8.00.

To sum up, through two methods of loop calculation and recursive calculation, we can implement C language exponentiation operation. Which method to use depends on actual needs and personal preference.

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