//Write a simple C program that calculation given above using 4 function.1.???=????????(?1,?2,?1,?2)2.???=????????(?1,?2,?1,?2)3.???=?????????????(?)where r is the radius4.?=????(?)where r is the radius
#include <stdio.h>
#include <math.h>
int n=5000;

float dis(float x1,float x2,float y1,float y2){ // function definition
    return sqrt(pow((x2-x1),2))+(pow((y2-y1),2)); // calculate distance
}
float diameter(float x1,float x2,float y1,float y2){ // function definition
      
    return dis(x1,x2,y1,y2); // return distance
}
double pitask(int n){  // function definition 

    if(n == 0){ // if n equal to 0 enter this block
    return 1;
    }
    else{ // else go this block
    return pow(-1,n)/(2 * n + 1)+pitask(n - 1); // execute recursive function
    }
}
float cir(float diameter){ // function definition
    return pitask(n)*diameter; // calculate circumference
}

float d(float diameter){ // function definition
    return pitask(n)*(diameter/2.00)*(diameter/2.00); // calculate area
}
int main(void){
    float x1,x2,y1,y2;
  
    printf("Please enter the coordinate of center of circle>>");
    scanf("%f %f",&x1 ,&y1);
    printf("Please enter the coordinate of point on circle>>");
    scanf("%f %f",&x2 ,&y2);
 
  float r= dis(x1,x2,y1,y2);
    printf("Distance of circle>>%f\n",2*r);
    printf("Diameter of circle>>%f\n",2*r);
    printf("Circumferenc of circle>>%f\n",cir(r));
    printf("Area of circle>>%f",d(r));
    return 0;
}