# include <stdio.h>
# include <math.h>
int main()
{ int a, b, c; float X1, X2, d; char ch;
  do
  { clrscr();
    printf("\n\n\t------------- ax^2+bx+c=0--------------\n");
    printf("\n\tplease input a,b,c.(int)!\n");
    printf("a="); scanf( "%f", &a );
    printf("b="); scanf( "%f", &b );
    printf("c="); scanf( "%f", &c );
    if ( a==0 )
     if ( b==0 )
      if ( c==0 )
      printf("\n\tThere are many root!\n");
      else
      printf("\n\tNo root!\n");
     else
     {
      X1=(-1.0*c)/b;
      X2==X1;
      printf("\n\tX1=%f\n\tX2=%f",&X1,&X2 );
     }
    else
    {
     d=b*b-4.0*a*c;
     if ( d==0 )
     {
      X1=-b/(2.0*a);
      X2==X1;
      printf("\n\tX1=%f\n\tX2=%f",&X1,&X2 );
     }
      else
      if ( d>0 )
      {
       X1=(-b+sqrt(d))/2.0*a;
       X2=(-b-sqrt(d))/2.0*a;
       printf("\n\tX1=%f\n\tX2=%f",&X1,&X2);
      }
       else
       {
        X1=(-b+sqrt(-d))/2.0*a;
        X2=(-b-sqrt(-d))/2.0*a;
        printf("\n\tX1=%fi\n\tX2=%fi",&X1,&X2);
       }
    }
    printf("\n\n\tContinue( Yes -- anykey / No -- 'n')?\n");
    ch=getch();
    if ( ch=='N' ) ch='n';
  } while ( ch!='n' );
  return 0;
}



我看了一下午无法解决- -

！我改一下看看

我刚学的，错了好多，谢谢指教

话说你用修改后的程序能算出正确答案吗