C语言考试练习题_一元二次方程 （C语言代码）

解题思路:运用求根公式进行分类讨论

注意事项: %c前加空格

参考代码：

# 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)

{

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

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

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

}

else if (0==delta)

{

printf ("有唯一解,x1= x2 =%lf\n",x1,x2);

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

}

else

{

printf ("无实数解!\n");

}

printf ("您想继续吗?(Y/N)");

scanf (" %c",&ch);                //%c前面必须加空格

}

    while ('Y'==ch|| 'y'==ch);

return 0;

}