How to output the circumference and area of ​​a circle in C language

In order to calculate the circumference and area of ​​a circle, you need to obtain its radius, then calculate the circumference (2 π radius) and area (π * radius squared) according to the formula, and finally output the results.

How to use C language to output the circumference and area of ​​a circle

In order to calculate and output the circumference and area of ​​a circle area, you need to follow the following steps:

1. Include the necessary header files

   <code class="c">#include <stdio.h>
   #include <math.h></code>

2. Define the radius of the circle
   Declare a floating point variable to store the radius of the circle. For example:

   <code class="c">float radius;</code>

3. Get the radius of the circle input
   Prompts the user to enter the radius of the circle and uses the scanf function to store the input value. For example:

   <code class="c">printf("请输入圆的半径：");
   scanf("%f", &radius);</code>

4. Calculate perimeter and area
   Use the formula of a circle to calculate perimeter and area. The perimeter is 2 * π * radius , and the area is π * radius squared . For example:

   <code class="c">float circumference = 2 * M_PI * radius;
   float area = M_PI * pow(radius, 2);</code>

5. Output results
   Use the printf function to output the calculated perimeter and area. For example:

   <code class="c">printf("周长：%.2f\n", circumference);
   printf("面积：%.2f\n", area);</code>

Full code example:

<code class="c">#include <stdio.h>
#include <math.h>

int main() {
    float radius;

    printf("请输入圆的半径：");
    scanf("%f", &radius);

    float circumference = 2 * M_PI * radius;
    float area = M_PI * pow(radius, 2);

    printf("周长：%.2f\n", circumference);
    printf("面积：%.2f\n", area);

    return 0;
}</code>

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