C++课堂练习一

#include<iostream>
#include<string>
using namespace std;

int main(){
    char addressee[50], sender[50];
    cout << "请输入收信人：" << endl;
    cin.getline(addressee, 50);
    cout << "请输入寄信人：" << endl;
    cin.getline(sender, 50);
    cout << "#################################" << endl;
    cout << addressee << endl;
    cout << endl;
    cout << "Happy birthday to you!" << endl;
    cout << endl;
    cout << "    sincerely yours " << sender << endl;
    cout << "#################################" << endl;
    return  0;   
}

#include<iostream>
using namespace std;
int main(){
    int a, b;
    int c;
    cout << "计算a+b，请输入a，b：" << endl;
    cin >> a >> b;
    c = a + b;
    cout << "c = " << c << endl;
    return 0;
}

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
    double money, years, rate, sum;
    cout << "请输入本金，年份，利率：" << endl;
    cin >> money >> years >> rate;
    while (money >= 0) 
    {
        sum = money * pow((1 + rate), years);
        cout << "本息和 = " << sum << endl;
        cout << "请输入本金，年份，利率(本金小于0时退出)：" << endl;
        cin >> money >> years >> rate;
    }
    return 0;
}