vector insert() 函式在 C++ STL 中


C++ STL 中的 vector insert() 函式有助於透過在指定位置的元素之前插入新元素來增加容器的大小。

這是 C++ STL 中預定義的函式。

我們可以使用三種語法插入值

1. 僅提及位置和值來插入值

vector_name.insert(pos,value);

2. 提及位置、值和大小來插入值

vector_name.insert(pos,size,value);

3. 從已填充的 vector 形式的另一個空 vector 插入值,透過提及應插入值的位置和已填充 vector 的迭代器

empty_eector_name.insert(pos,iterator1,iterator2);

演算法

Begin
   Declare a vector v with values.
   Declare another empty vector v1.
   Declare another vector iter as iterator.
   Insert a value in v vector before the beginning.
   Insert another value with mentioning its size before the beginning.
   Print the values of v vector.
   Insert all values of v vector in v1 vector with mentioning the iterator of v vector.
   Print the values of v1 vector.
End.

範例

 現場演示

#include<iostream>
#include <bits/stdc++.h>
using namespace std;

int main() {
   vector<int> v = { 50,60,70,80,90},v1;        //declaring v(with values), v1 as vector.
   vector<int>::iterator iter;                  //declaring an iterator
   iter = v.insert(v.begin(), 40);              //inserting a value in v vector before the beginning.
   iter = v.insert(v.begin(), 1, 30);           //inserting a value with its size in v vector before the beginning.
   cout << "The vector1 elements are: \n";
   for (iter = v.begin(); iter != v.end(); ++iter)
      cout << *iter << " "<<endl;             // printing the values of v vector
   v1.insert(v1.begin(), v.begin(), v.end()); //inserting all values of v in v1 vector.
   cout << "The vector2 elements are: \n";
   for (iter = v1.begin(); iter != v1.end(); ++iter)
      cout << *iter << " "<<endl;            // printing the values of v1 vector
   return 0;
}

輸出

The vector1 elements are:
30
40
50
60
70
80
90
The vector2 elements are:
30
40
50
60
70
80
90

更新於: 2019 年 7 月 30 日

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