这是一段计算一元二次不等式的代码，问题是每次运行黑窗口都无法正确暂停，system("PAUSE")语句不是最后暂停，而是在输出结果之前暂停，为什么会出现这种情况？感觉有时候好用，遇见switch和if语句就不太好用，不知道其他情况下怎么样。谢谢答疑~


#include <iostream.h>
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include<conio.h>

void main()
{

    double a,b,c,delta,x1,x2;
    a=1;
    b=2;
    c=1;

    //cin>>a>>b>>c;

    if (a==0&&b==0)
        cout<<"feiyiyuanercifangcheng\n";
    else
        if (a==0&&b!=0)        //bx+c=0
            cout<<"gaifangchengweiyiyuanyicifangcheng,jiewei:"<<-c/b<<'\n';
         else
         {
             delta=b*b-4*a*c;
             if (delta<0)
                 cout<<"fangchengwujie\n";
             else
                 if (delta==0)
                     cout<<"gaifangchengyoulianggexiangdengdeshishujie:"<<-b/(2*a)<<'\n';
                 else
                 {
                     x1=(-b+sqrt(delta))/(2*a);
                     x2=(-b-sqrt(delta))/(2*a);
                     cout<<"gaifangchengyoulianggebudengdeshigenjie:"<<x1<<'\t'<<x2<<'\n';
                     system("PAUSE");
                 }
         }

    system("PAUSE");

}

用getch()代替。先加上conio.h