“转换二进制”；这是我做的，运行时总是负数，我已经看不清楚了，大家帮我看看吧，改一改，谢谢啦~~~


#include<iostream>
#include<fstream>
#include<sstream>
#include<vector>
#include<cmath>
using namespace std;
//---------------------------------------------------
int main()
{
 cout<<"输入要转换的二进制数 : "<<endl;
 string s;
 vector<int> x;
 cin>>s;
 istringstream sin(s);
 int sum = 0;
 for(int a ;sin>>a;)
     x.push_back(a);
 int d=x.size();
 for(int i = 0; i<=d ;++i)
 {
  double o=pow(2.0,d-i);
  sum+=(x[i] * o);
 }
 cout<<sum<<endl;
 return 0;
}

#include <iostream>
#include <sstream>
#include <vector>
using namespace std;

int main()
{
    cout<<"输入要转换的二进制数 : "<<endl;
    string s;
    cin >> s;

    vector<char> x;
    istringstream sin(s);
    for( char a ;sin>>a; )
        x.push_back(a);

    int sum = 0;
    size_t d = x.size();
    for( size_t i=0; i<d; ++i )
    {
        int o = 1<<(d-i-1);
        sum += (x[i]-'0') * o;
    }
    cout << sum << endl;

    return 0;
}

int main2()
{
    string s;
    cin >> s;

    int n = 0;
    for( size_t i=0; i<s.size(); ++i )
        n |= (s[i]-'0')<<(s.size()-i-1);

    cout << n << endl;

    return 0;
}

#include <bitset>
int main3()
{
    string s;
    cin >> s;

    std::bitset<sizeof(unsigned long)*8> x( s );
    unsigned long n = x.to_ulong();

    cout << n << endl;

    return 0;
}

#include <iostream>
using namespace std;
#include <stdlib.h>
int main()
{
    cout<<"**********\n十进制转二进制·练手**********\n(<=65535)\n";
    int D[16];
    D[0]=1;
    for(int i=0;i<16;i++)
    {
        D[i+1]=D[i]*2;
        cout<<D[i]<<endl;
    }
    cout<<"Please Type in an Integer(<65535):";
    int ta;cin>>ta;cout<<endl;
    int i=16;
    for(;i>=0;i--)
    {
        if(ta<D[i]) cout<<0;
        else if(ta>=D[i])
        {
            cout<<1;
            ta=ta-D[i];
        }
        if((i)%4==0) cout<<".";
    }
    cout<<endl;
    system("pause");
    return 0;
}

另一种思路 -