1

#include <iostream>
#include <cmath>
using namespace std;
class A{
private:int a;// 判断一个数是否为质数bool isP(int num) {if (num<2) return false;for (int i=2;i<=sqrt(num);i++) {if (num % i == 0) {return false;}}return true;}
public:// 构造函数A():a(0){}// 设置成员a的值void set(int value) {a = value;}// 计算并打印1到a之间所有数字的和void Sum() {int sum = 0;for (int i = 1; i <= a; ++i) {sum += i;}cout << "1 到 " << a << " 和 = " << sum <<endl;}// 计算并打印1到a之间所有数字的乘积void Product() {long long product = 1; // 使用long long防止乘积溢出for (int i = 1; i <= a; ++i) {product *= i;}cout << "1 到 " << a << " 乘积 = " << product <<endl;}// 输出1到a之间的所有质数void PrimeNumber() {cout << "1 到 " << a << " 中的质数 = ";bool flag = true;for (int i = 2; i <= a; ++i) {if (isP(i)) {if (!flag) {cout << ",";}cout << i;flag = false;}}cout<<endl;}
};
int main() {A no;int a=0;cout<<"输入a:"<<endl;cin>>a;no.set(a);no.Sum();no.Product();no.PrimeNumber();return 0;
}

 2

#include <iostream>
using namespace std;
class A{
private:int count;
public:A():count(0){}char MyGetChar(){if (count < 10){return '0' + count++;}else{count = 0; // 重置计数return '0' + count++;}}
};
class B{
private:char count;
public:B():count('a'){}char MyGetChar(){char ret = count;count++;if (count > 'z'){count = 'a'; // 重置计数}return ret;}
};
int main(){A a;B b;for (int i=0;i<35;i++) {if(i<20)cout << a.MyGetChar();if (i<26)cout<<b.MyGetChar();}cout<<endl;return 0;
}

3

#include <iostream>
#include <list>
using namespace std;
class A {
private:list<char> n;
public:void addNumber(char num) {n.push_back(num);}void sortNumbers() {n.sort();}void dump() {cout << "存放数字的类，输出: ";list<char>::iterator it;for(it=n.begin();it!=n.end();it++) {cout<<*it;}cout<<endl;}
};class B {
private:list<char> l;public:void addLetter(char l) {this->l.push_back(l);}void sortLetters() {l.sort();}void dump() {cout << "存放字母的类，输出: ";list<char>::iterator it;for(it=l.begin();it!=l.end();it++) {cout<<*it;}cout<<endl;}
};int main() {string input;cout << "请输入一个字符串: ";cin >> input;A a;B b;for (int i = 0; i <static_cast<int>(input.size()); ++i) {char c = input[i];if (c >= '0' && c <= '9') {a.addNumber(c);} else if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {b.addLetter(c);}}b.sortLetters();a.sortNumbers();b.dump();a.dump();return 0;
}