1)栈

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

enum error{overflow,underflow,success};
const int maxlen=100;

class  stack
{
public:
     stack();//初始化
     ~stack();//析构
    bool empty() const;//判断空
    bool full() const;//判断满
    int get_front(int &x)const;//取栈顶元素
    error push(const int x);//入栈
    error pop();//出栈
private:
    int count;//统计栈中元素的个数
    int data[maxlen];//存储栈中数据
};

/*
*初始化栈
*/
 stack:: stack()
{
    count=0;
}
 
 /*
 *判断为空
 */
bool stack::empty() const{
    if(count==0)return true;
    return false;
}

/*
*判断为满
*/
bool stack::full() const{
    if(count==maxlen)return true;
    return false;
}

/*
*取栈顶元素
*/
int stack::get_front(int &x)const{
    if(empty())return underflow;
    x=data[count-1];
    return success;
}

/*
*入栈
*/
error stack::push(const int x){
    if(full())return overflow;
    data[count]=x;
    count++;
    return success;
}

/*
*出栈
*/
error stack::pop(){
    if(empty())return underflow;
    count--;
    return success;
}
stack::~stack()
{
    while(!empty())pop();
}

/*
*十进制数转化为八进制数
*/
int xchg(int n,stack s){
    cout<<"十进制:["<<n<<"]->8进制:";
    int mod,x;
    while(n!=0){
        mod = n % 8;
        s.push(mod);
        n/=8;
    }
    while(s.empty()!=true){
        s.get_front(x);
        cout<<x;
        s.pop();
    }
    cout<<endl;
    return 0;
}
int main()
{
    stack s;
    xchg(100,s);
    return 0;
}