C语言题“输入系数的有效值，计算一元二次方程的实根和虚根”怎么编？

#include <stdio.h>

#include <math.h>

int main(void)

{

double a,b,c,disc,x1,x2,imagpart,realpart,m,n

printf("please input a,b,c(a!=0):\n")

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

disc = b * b - 4 * a * c

m = - b / (2 * a)

n = sqrt(disc) / (2 * a)

if (fabs(disc) <1e-8)

{

x1 = x2 = m //有两个相等实根

printf("x1=x2=%8.2f\n",x1)

}

else

if (disc >0)

{

x1 = m + n,x2 = m - n//有两个不等实根

printf("x1=%8.2f\t,x2=%8.2f\n",x1,x2)

}

else

{

realpart = m

imagpart = sqrt(-disc) / (2 * a) //有两个共轭复根

printf("x1=%8.2f+%.2fi\t,x2=%8.2f-%.2fi\n",realpart,imagpart,realpart,imagpart)

}

return 0

}

对于ax^2+bx+c=0

int panduan(int a,int b,int c)

{

int m

m=b*b-4*a*c

return(m)

}

void main()

{int a,b,c,flag,x1,x2,ture,virture

printf("请依次输入二次方程的系数：＼n”)

scanf("%d %d %d",&a,&b,&c)

flag=panduan(a,b,c)

if(flag>0)

{x1=(-b+sqr(flag))/(2*a)

x2=(-b-sqr(flag))/(2*a)

printf("两个不相等的实根为:x1=%d,x2=%d",x1,x2)

}

else if(flag==0)

{x1=-b/(2*a)

printf("两个相等的实根为:x1=x2=%d",x1)

}

else

{ture=-b/(2*a)

virture=sqr(-flag)/(2*a)

printf("两个不相等的虚根为:x1=%d+%di,x2=%d-%di",ture,virture,ture,virture)

}

}

程序的健壮性不是很好，适用于int型的，你可以将所有的变量都改为float，这样就可以处理其他的问题。要求输入绝对正确，3个系数之间以空格隔开！

# include <stdio.h>

# include <math.h>

int main(void)

{

double a, b, c

double delta

double x1, x2

char ch

do

{

printf("请输入一元二次方程的三个系数:\n")

printf("a = ")

scanf("%lf", &a)

printf("b = ")

scanf("%lf", &b)

printf("c = ")

scanf("%lf", &c)

delta = b*b - 4*a*c

if (delta >0)

{

x1 = (-b + sqrt(delta)) / (2*a)

x2 = (-b - sqrt(delta)) / (2*a)

printf("有两个解，x1 = %lf, x2 = %lf\n", x1, x2)

}

else if (0 == delta)

{

x1 = x2 = (-b) / (2*a)

printf("有唯一解，x1 = x2 = %lf\n", x1, x2)

}

else

{

printf("无实数解!\n")

}

printf("您想继续么(Y/N): ")

scanf(" %c", &ch) //%c前面必须得加一个空格 原因略

} while ('y'==ch || 'Y'==ch)

return 0

}

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