进制转换

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
using namespace std;
string s;//全局变量
int main(int argc, char* argv[])
{
int n;
while(cin>>n)
{
if(n==0)
{
cout<<" 0-->0\n";
continue;
}
s="";
for(int a=n;a; a=a/2)
{
//s=s+(a%2?'1':'0');
if(a%2==0)
{
s=s+'0';
}
else
{
s=s+'1';
}
}
std::reverse(s.begin(),s.end());  //反转
cout<<n<<(n<0?"-->-":"-->")<<s<<"\n";
}
return 0;
}

#include <iostream>
#include <math.h>
using namespace std;
int main()
{
int a,b=0,m,k=0;
cout<<"输入一个二进制"<<endl;
cin>>a;
while (a!=0)
{
m=a%10;
a/=10;
b+=m*pow(2,k++);
}
cout<<"对应十进制为"<<endl;
cout<<b<<endl;
}