C++程序的问题

#include<iostream>
using namespace std;
void main()
{
double a,b,c,m,n;
char i;
cout<<"请输入a=";
cin>>a;
cout<<"请输入b=";
cin>>b;
cout<<"请输入c=";
cin>>c;
if(a=0)
cout<<"x="<<-c/b<<endl;
else
if(b*b-4*a*c==0)
cout<<"x1=x2="<<-b/2*a<<endl;
else
if(b*b-4*a*c>0)
{
m=(-b+sqrt(b*b-4*a*c))/2*a;
cout<<"x1="<<m<<endl;
n=(-b-sqrt(b*b-4*a*c))/2*a;
cout<<"x2="<<n<<endl;
}
else
{
cout<<"x1="<<-b/(2*a)<<"+"<<sqrt(b*b-4*a*c)/(2*a)<<i<<endl;
cout<<"x2="<<-b/(2*a)<<"-"<<sqrt(b*b-4*a*c)/(2*a)<<i<<endl;
}

} 错在哪

等号写成了赋值号

我在VC下面给你修改了,经测试程序能运行,并能得出正确结果,用到开平方函数一定要有#include<math.h>头文件,其次在最后的输出复数i时,前面的char i;理解有误,这只是定义了一个字符变量,里面没有任何字符,你想输出复数里的i字符,则把'i'赋予它,即char i='i';

#include<iostream> #include<math.h> using namespace std; void main() { double a,b,c,m,n; char i='i'; cout<<"请输入a="; cin>>a; cout<<"请输入b="; cin>>b; cout<<"请输入c="; cin>>c; if(a==0) cout<<"x="<<-c/b<<endl; else if(b*b-4*a*c==0) cout<<"x1=x2="<<-b/(2*a)<<endl; else if(b*b-4*a*c>0) { m=(-b+sqrt(b*b-4*a*c))/(2*a); cout<<"x1="<<m<<endl; n=(-b-sqrt(b*b-4*a*c))/(2*a); cout<<"x2="<<n<<endl; } else { cout<<"x1="<<-b/(2*a)<<"+"<<sqrt(-(b*b-4*a*c))/(2*a)<<i<<endl; cout<<"x2="<<-b/(2*a)<<"-"<<sqrt(-(b*b-4*a*c))/(2*a)<<i<<endl; }

错误太多了，看加粗的部分吧：

#include<iostream> #include<math.h> using namespace std; int main() { double a,b,c,m,n; char i = 'i'; cout<<"请输入a="; cin>>a; cout<<"请输入b="; cin>>b; cout<<"请输入c="; cin>>c; if(a==0) cout<<"x="<<-c/b<<endl; else if(b*b-4*a*c==0) cout<<"x1=x2="<<-b/2*a<<endl; else if(b*b-4*a*c>0) { m=(-b+sqrt(b*b-4*a*c))/2*a; cout<<"x1="<<m<<endl; n=(-b-sqrt(b*b-4*a*c))/2*a; cout<<"x2="<<n<<endl; } else { cout<<"x1="<<-b/(2*a)<<"+"<<sqrt(-(b*b-4*a*c))/(2*a)<<i<<endl; cout<<"x2="<<-b/(2*a)<<"-"<<sqrt(-(b*b-4*a*c))/(2*a)<<i<<endl; } }