1 #include <iostream>
 2 #include <queue>
 3 #include <climits>
 4 #include <algorithm>
 5 #include <memory.h>
 6 #include <stdio.h>
 7 #include <ostream>
 8 #include <vector>
 9 #include <list>
10 #include <cmath>
11 #include <string>
12 #include <stdexcept>
13 using namespace std;
14 
15 class stack3parts
16 {
17     const int stackSize;
18     int top1;
19     int top2;
20     int top3;
21     int* data;
22 public:
23     stack3parts(int paramSize):stackSize(paramSize),top1(0),top2(paramSize),top3(2*paramSize)
24     {
25         data = new int[paramSize*3];
26     }
27 
28     void push(int stackNum,const int &elem)
29     {
30         switch(stackNum)
31         {
32         case 1:
33             if(top1 == stackSize)
34                 throw std::out_of_range("stack1 is full!");
35             data[top1++] = elem;
36             break;
37         case 2:
38             if(top2 == 2*stackSize)
39                 throw std::out_of_range("stack2 is full!");
40             data[top2++] = elem;
41             break;
42         case 3:
43             if(top3 == 3*stackSize)
44                 throw std::out_of_range("stack3 is full!");
45             data[top3++] = elem;
46             break;
47         }
48     }
49 
50     int pop(int stackNum)
51     {
52         switch(stackNum)
53         {
54         case 1:
55             if(top1 == 0)
56                 throw std::out_of_range("stack1 is empty!");
57             top1--;
58             return data[top1];
59             break;
60         case 2:
61             if(top2 == stackSize)
62                 throw std::out_of_range("stack2 is empty!");
63             top2--;
64             return data[top2];
65             break;
66         case 3:
67             if(top3 == 2*stackSize)
68                 throw std::out_of_range("stack3 is empty!");
69             top3--;
70             return data[top3];
71             break;
72         }
73     }
74 };
75 int main()
76 {
77     stack3parts s(3);
78     s.push(1,2);
79     s.push(2,3);
80     s.push(3,4);
81 
82     cout<<s.pop(1)<<endl;
83     cout<<s.pop(2)<<endl;
84     cout<<s.pop(3)<<endl;
85 
86     s.pop(1);
87     return 0;
88 }

这个思路是对一个数组进行固定的大小分配，这样缺点是资源得不到充分利用