C++ 程序实现向量


向量是一个动态数组,如果插入或删除元素,它可以自动调整自身大小。向量元素包含在连续的存储中,容器会自动处理存储。

下面给出了实现向量的程序 -

范例

#include <iostream>
#include <vector>
#include <string>
#include <cstdlib>

using namespace std;
int main() {
   int ch, val;
   vector<int> vec;
   cout<<"1)Insert Element into the Vector"<<endl;
   cout<<"2)Delete Last Element of the Vector"<<endl;
   cout<<"3)Print size of the Vector"<<endl;
   cout<<"4)Display Vector elements"<<endl;
   cout<<"5)Clear the Vector"<<endl;
   cout<<"6)Exit"<<endl;

   do {
      cout<<"Enter your Choice: "<<endl;
      cin>>ch;
      switch(ch) {
         case 1:
         cout<<"Enter value to be inserted: "<<endl;
         cin>>val;
         vec.push_back(val);
         break;
         case 2:
         cout<<"Last Element is deleted."<<endl;
         vec.pop_back();
         break;
         case 3:
         cout<<"Size of Vector: ";
         cout<<vec.size()<<endl;
         break;
         case 4:
         cout<<"Displaying Vector Elements: ";
         for (int i = 0; i < vec.size(); i++)
         cout<<vec[i]<<" ";
         cout<<endl;
         break;
         case 5:
         vec.clear();
         cout<<"Vector Cleared"<<endl;
         break;
         case 6:
         cout<<"Exit"<<endl;
         break;
         default:
         cout<<"Error....Wrong Choice Entered"<<endl;
      }
   } while (ch!=6);
   return 0;
}

输出

以上程序的输出如下

1)Insert Element into the Vector
2)Delete Last Element of the Vector
3)Print size of the Vector
4)Display Vector elements
5)Clear the Vector
6)Exit

Enter your Choice: 1
Enter value to be inserted: 5
Enter your Choice: 1
Enter value to be inserted: 2
Enter your Choice: 1
Enter value to be inserted: 8
Enter your Choice: 1
Enter value to be inserted: 6
Enter your Choice: 3
Size of Vector: 4
Enter your Choice: 4
Displaying Vector Elements: 5 2 8 6
Enter your Choice: 2
Last Element is deleted.
Enter your Choice: 3
Size of Vector: 3
Enter your Choice: 4
Displaying Vector Elements: 5 2 8
Enter your Choice: 5
Vector Cleared
Enter your Choice: 3
Size of Vector: 0
Enter your Choice: 4
Displaying Vector Elements:
Enter your Choice: 9
Error....Wrong Choice Entered
Enter your Choice: 6
Exit

在以上程序中,先是定义了向量,然后向用户提供了一个菜单,让他们选择向量操作。如下所示 −

vector<int> vec;
cout<<"1)Insert Element into the Vector"<<endl;
cout<<"2)Delete Last Element of the Vector"<<endl;
cout<<"3)Print size of the Vector"<<endl;
cout<<"4)Display Vector elements"<<endl;
cout<<"5)Clear the Vector"<<endl;
cout<<"6)Exit"<<endl;

使用 do while 循环输入用户选择,使用 switch 语句根据选择实现操作。不同的操作包括将元素插入向量、从向量删除元素、打印向量的长度、显示向量的元素、清除向量和退出。代码片段如下 −

do {
   cout<<"Enter your Choice: "<<endl;
   cin>>ch;
   switch(ch) {
      case 1:
      cout<<"Enter value to be inserted: "<<endl;
      cin>>val;
      vec.push_back(val);
      break;
      case 2:
      cout<<"Last Element is deleted."<<endl;
      vec.pop_back();
      break;
      case 3:
      cout<<"Size of Vector: ";
      cout<<vec.size()<<endl;
      break;
      case 4:
      cout<<"Displaying Vector Elements: ";
      for (int i = 0; i < vec.size(); i++)
      cout<<vec[i]<<" ";
      cout<<endl;
      break;
      case 5:
      vec.clear();
      cout<<"Vector Cleared"<<endl;
      break;
      case 6:
      cout<<"Exit"<<endl;
      break;
      default:
      cout<<"Error....Wrong Choice Entered"<<endl;
   }
} while (ch!=6);

更新于:25-6 月-2020

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