if(disc<0)8<0为假 printf( has not real roots\n i else p=b/(2.0*a);p的值变为-1 q=sqrt(disc)/(20*a);q的值变为071 X1=p+qX1的值变为029 x2=p-qx2的值变为-171 printf( real roots:(nx1=%/07.2f\n x2=%72fn"x1X2); real roots: return o 1=-8.29 2 1.71if (disc<0) printf(“has not real roots\n”); else { p=-b/(2.0*a); q=sqrt(disc)/(2.0*a); x1=p+q; x2=p-q; printf(“real roots:\nx1=%7.2f\n x2=%7.2f\n”,x1,x2); } return 0; } 8<0为假 p的值变为-1 q的值变为0.71 x1的值变为-0.29 x2的值变为-1.71