C语言程序设计教程（第三版）课后习题8.2 （C语言代码）

解题思路:





注意事项:一定要细心！





参考代码:

#include <stdio.h>

#include <math.h>

int test1(double a,double b,double c)

{

double t1=-b/2*a, t2=sqrt(b*b-4*a*c)/2*a;

printf("x1=%.3f x2=%.3f\n",t1+t2,t1-t2);

return 0;

}

int test2(double a,double b, double c)

{

double t1=-b/2*a, t2=sqrt(b*b-4*a*c)/2*a;

printf("x1=%.3f x2=%.3f\n",t1+t2,t1-t2);

return 0;

}

int test3(double a,double b,double c)

{

double t1=-b/(2*a), t2=sqrt(4*a*c-b*b)/(2*a);

printf("x1=%.3f+%.3fi x2=%.3f-%.3fi\n",t1,t2,t1,t2);

return 0;

}

int main()

{

double a=4,b=1,c=1;

//scanf("%lf %lf %lf",&a,&b,&c);

double d=b*b-4*a*c;

if(d>0)

{

test1(a,b,c);

}

else if(d==0)

{

test2(a,b,c);

}

else if(d<0)

{

test3(a,b,c);

}

return 0;

}