#include<cstdlib>
using namespace std;
int main()
{ double a,b,c,s,v;
cout<<"請輸入立方體的三條邊長,用空格隔開,按ENTER鍵結束輸入:";
cin>>a>>b>>c;
s=2*(a*b+a*c+b*c);
v=a*b*c;
cout<<"立方體的三條邊為:a="<<a<<" "<<"b="<<b<<" "<<"c="<<c<<endl;
cout<<"立方體的表面積為:"<<endl<<"S=2*(a*b+a*c+b*c)="<<s<<endl;
cout<<"立方體的體積為:"<<endl<<"V=a*b*c="<<v;
system("pause");
return 0;} 第二題:#include<iostream>
#include<cstdlib>
using namespace std;
int main()
{ float a,b;
cout<<"輸入兩個數,用空格隔開:";
cin>>a>>b;
cout<<"交換前的兩個數為"<<a<<"和"<<b<<endl;
float temp;
temp=a,a=b,b=temp;
cout<<"交換後的兩個數為"<<a<<"和"<<b<<endl;
system("pause");
return 0;} 第三題:#include<iostream>
#include<cstdlib>
#include<cmath>
#include<iomanip>
using namespace std;
int main()
{ double q,sum=0;
int n;
cout<<"輸入等比數列的公比q和項數n,用空格隔開:";
cin>>q>>n;
cout<<"等比數列的各項為:"<<endl;
for(int i=0;i!=n;i++)
{cout<<setprecision(4)<<pow(q,i)<<" ";<br> sum+=pow(q,i);<br> if((i+1)%10==0) cout<<endl;}
cout<<"等比數列的前n項的和為:"<<endl;
cout<<"1+q+q^2+...+q^n="<<setprecision(4)<<sum<<endl;
system("pause");
return 0;}我也是初學者,***同進步哈