把scanf中的逗号去掉吧,你如果加上逗号,那你输入数据时必须加上与之对应的逗号,才能正常读入数据。
#include <stdio.h>
#include <math.h>
int main()
{
double a, b, c, disc, x1, x2, p, q;
scanf("%lf %lf %lf", &a, &b, &c);
disc = b * b - 4 * a * c;
if (disc < 0)
printf("无解");
else
{
p = -b / (2.0 * a);
q = sqrt(disc) / (2.0 * a);
x1 = p - q;
x2 = p + q;
printf("real roots:\nx1=%.2f x2=%.2f", x1, x2);
}
return 0;
}