#include <iostream>using namespace std;
class Num
{
private:int a;
public:Num() {}Num(int a):a(a){}//设置a的值void set(int a){this->a=a;}//1-a的和void Sum(){if(a<1){cout<<"a<1"<<endl;return;}int sum=0;for(int i=1;i<=a;i++){sum+=i;}cout<<"Sum="<<sum<<endl;}//1-a的乘积void Porduct(){if(a<1){cout<<"a<1"<<endl;return;}int product=1;for(int i=1;i<=a;i++){product*=i;}cout<<"Product="<<product<<endl;}//1-a的所有质数void PrimeNumber(){if(a<1){cout<<"a<1"<<endl;return;}cout<<"PrimeNumber:";for(int i=2;i<=a;i++){int flag=0;for(int j=2;j<i;j++){if(i%j==0){flag++;}}if(0==flag){cout<<i<<" ";}}cout<<endl;}
};
int main()
{Num num1;num1.set(10);num1.Sum();num1.Porduct();num1.PrimeNumber();return 0;}

 

2. 已知C风格的字符串，完成对字符串通过下标访问时的异常处理机制(越界访问)

#include <iostream>
#include <cstring>
using namespace std;class Str
{
private:char *str;int size;
public:Str() {}Str(const char *str):str(nullptr),size(0){size=strlen(str);this->str=new char[size+1];strcpy(this->str,str);}char &at(int pos){if(pos>=size){throw char(1);}return *(str+pos);}
};
int main()
{Str s1("hello");cout<<s1.at(3)<<endl;cout<<s1.at(5)<<endl;return 0;
}

 

 

#include <iostream>using namespace std;
class A
{
private:static char a;
public:A() {}static void MyGetChar(){if(a>'9'){a='0';}cout<<a;a++;}
};
char A::a='0';
class B
{
private:static char b;
public:B() {}static void MyGetChar(){if(b>'z'){
//            cout<<endl;b='a';}cout<<b;b++;}
};
char B::b='a';
int main()
{for(int i=0;i<26;i++){if(i<20){A().MyGetChar();}B().MyGetChar();}cout<<endl;for(int i=0;i<26;i++){if(i<20){A().MyGetChar();}B().MyGetChar();}return 0;
}

 

#include <iostream>using namespace std;
class A
{
private:string str;
public:A() {}A(string str):str(str){int j=0;for(unsigned int i=0;i<this->str.size();i++){if(this->str.at(i)>='a'&&this->str.at(i)<='z'){this->str.at(j)=this->str.at(i);j++;}}this->str.resize(j);}void dump(){char temp;for(unsigned int i=0;i<str.size()-1;i++){for(unsigned int j=0;j<str.size()-1-i;j++){if(str.at(j)>str.at(j+1)){temp=str.at(j);str.at(j)=str.at(j+1);str.at(j+1)=temp;}}}cout<<str<<endl;}};
class B
{
private:string str;
public:B() {}B(string str):str(str){int j=0;for(unsigned int i=0;i<this->str.size();i++){if(this->str.at(i)>='0'&&this->str.at(i)<='9'){this->str.at(j)=this->str.at(i);j++;}}this->str.resize(j);}void dump(){char temp;for(unsigned int i=0;i<str.size()-1;i++){for(unsigned int j=0;j<str.size()-1-i;j++){if(str.at(j)>str.at(j+1)){temp=str.at(j);str.at(j)=str.at(j+1);str.at(j+1)=temp;}}}cout<<str<<endl;}
};
int main()
{string str;cin>>str;A a(str);a.dump();B b(str);b.dump();return 0;
}