程序代码：

#include<iostream>
using namespace std;

int main()
{
    const int da_to_ho=24;
    const int ho_to_mi=60;
    const int mi_to_se=60;
    long s;
    long days,hours,minutes,seconds;
    cout<<"enter the number of seconds:";
    cin>>s;
    days=s/da_to_ho/ho_to_mi/mi_to_se;
    hours=s%(da_to_ho*ho_to_mi*mi_to_se)/(ho_to_mi*mi_to_se);
    //醉醉的   当初写上一个语句是全部用的是除法  结果小于0出错 杀毒软件说我的这个程序有可能是木马哈哈哈
    minutes=s%(ho_to_mi*mi_to_se)/(mi_to_se);
    seconds=s%(mi_to_se);
    cout<<s<<" seconds ="<<days<<"days,"<<hours<<"hours,"<<minutes<<"minutes,"<<seconds<<"seconds\n";
    return 0;
}

程序代码：

#include<iostream>
using namespace std;
int main()
{
    cout.setf(ios_base::fixed,ios_base::floatfield);
    double us,world;//题目要求是longlong类型，可是系统不支持，只能用double来代替。
    cout<<"enter the world's population: ";
    cin>>world;
    cout<<"enter the population of the us: ";
    cin>>us;
    const double n=100;
    double percent=us/world*n;
    cout<<"the population of the us is "<<percent<<"% of the world population.";
    return 0;
}