第七周 项目二 并联电阻

</pre><pre class="cpp" name="code">#include <iostream>
using namespace std;

int main()
 {   double r,r1,r2;
     cout<<"输入两个电阻r1与r2的阻值";
     cin >>r1 >>r2;
     r=1/(1/r1+1/r2);
    cout << "并联后的阻值为:" << r<<endl;
    return 0;
 }
</pre><pre class="cpp" name="code">#include <io