一元二次方程求解

/*the solution oif equations */

#include<stdio.h>

#include<math.h>

int main()

{

double a, b, c;

double delta;

double x1, x2;

char ch;

do

{

printf("请输入方程的三个参数:\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("方程有两个实数根：\n\n");

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

}

else if (delta == 0)

{

x1 = -b / (2*a);

printf("方程只有一个实数根：\n\n");

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

}

else

printf("方程无实数根 ！\n\n");

printf("想继续吗？ Y/N ");

scanf(" %c", &ch);

printf("\n");

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

return 0;

}