8-19.cpp

能判断二次函数是否有根

/*3208006411*/
#include<stdio.h>
#include<math.h>

void main()
{
float bulk(float r,float pi);
float area(float r,float pi);
float grith(float r,float pi);
float r,pi;float b,a,g;
printf("please input the num r:\n");
scanf("%f",&r);
int s;
float n,t;
t=1;pi=0;n=1.0;s=1;
while(fabs(t)>1e-6)
{pi=pi+t;
n=n+2;
s=-s;
t=s/n;
}
pi=pi*4;
b=bulk(r,pi);
a=area(r,pi);
g=grith(r,pi);
printf("bulk=%4.2f\n",b);
printf("girth=%4.2f\n",g);
printf("area=%4.2f\n",a);
}

float bulk(float r,float pi)
{float b;
b=1.33333*pi*r*r*r;
return(b);}

float grith(float r,float pi)
{float g;
g=pi*2*r;
return(g);
}
float area(float r,float pi)
{float a;
a=pi*r*r;
return(a);}