#include
#include
voidmain()
{
floata,b,c;
floatdisc,x1,x2,realpart,imagpart;
printf("请输入系数a、b、c(以空格隔开):n");
scanf("%f%f%f",&a,&b,&c);
printf("Theequationis:%fx^2+%fx+%f=0n",a,b,c);
printf("Therootoftheequationis:n");
if(a==0)/*二次项系数为0,即为一元一次方程的情况*/
{
if(b==0&&c!=0)
printf("无解!n");
elseif(b==0&&c==0)
printf("解是任意的.n");
else
printf("%fn",(-c)/b);
}
else/*接下来,是a不为0的情况*/
{
disc=b*b-4*a*c;
if(disc==0)/*判别式等于0时*/
printf("%fn",(-b)/(2*a));
elseif(disc>0)/*判别式大于0时*/
{
x1=(-b+sqrt(disc))/(2*a);
x2=(-b-sqrt(disc))/(2*a);
printf("%fand%fn",x1,x2);
}
else/*最后是判别式小于0,有两个复数解*/
{
realpart=-b/(2*a);
imagpart=sqrt(-disc)/(2*a);
printf("complexroots:n");
printf("%f+%fin",realpart,imagpart);
printf("%f-%fin",realpart,imagpart);
}
}
}