怎样vector内部的Modifiers(功能)进行实现 ?(详细 ! ! !)

一时失言乱红尘 2022-11-15 11:15 175阅读 0赞

![在这里插入图片描述][20210331143542911.png]

### vector5 ###

*  Modifiers(功能实现)
 *   *  1.assign
     *   *  1)通过输入对应元素来改变
         *  2) 通过迭代器来改变
     *  2.push\_back
     *  3.pop\_back
     *  4.insert
     *   *  1)插入单个字符
         *  2)插入多个
         *  3)插入对应范围内的字符串
     *  5.erase
     *   *  1)删除对应位置的字符
         *  2)删除范围内的字符串

# Modifiers(功能实现) #

这里主要涉及的就是对于单个元素的操作,主要理解和熟练使用这些操作的作用.  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70]

## 1.assign ##

### 1)通过输入对应元素来改变 ###

**用来改变对应vector内部的空间元素值和空间内字节的大小**  
![在这里插入图片描述][20210331144305802.png]

string s("1234");		//创建String类
    	vector<char>v(s.begin(), s.end());	//简单的创建赋值
    
    	v.assign(10, 'a');		//将vector内部的空间和对应的字符都发生改变

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 1]

### 2) 通过迭代器来改变 ###

![在这里插入图片描述][20210331144941871.png]

string s("1234");		
    	vector<char>v(s.begin(), s.end());	
    
    	string s2("abcdef");
    	
    	v.assign(s2.begin(), s2.end());  //用迭代器来进行元素的输入变化

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 2]

## 2.push\_back ##

![在这里插入图片描述][20210331151327836.png]

string s("1234");
    	vector<char>v(s.begin(), s.end());
    
    	//对下面的元素进行尾插
    	v.push_back('1');
    	v.push_back('2');
    	v.push_back('3');
    	v.push_back('4');
    	v.push_back('5');

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 3]

## 3.pop\_back ##

![在这里插入图片描述][20210331151431400.png]

v.push_back('1');
    	v.push_back('2');
    	v.push_back('3');
    	v.push_back('4');
    	v.push_back('5');
    
    	v.pop_back();	//将尾部的元素删除,执行5次
    	v.pop_back();
    	v.pop_back();
    	v.pop_back();
    	v.pop_back();

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 4]

## 4.insert ##

### 1)插入单个字符 ###

![在这里插入图片描述][20210331152730486.png]

v.insert(v.begin(), '0');		//首元素位置插入0

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 5]

### 2)插入多个 ###

![在这里插入图片描述][20210331152745868.png]

v.insert(--v.end(), 5,'a');		//倒数第二个元素的位置插入5个a

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 6]

### 3)插入对应范围内的字符串 ###

![在这里插入图片描述][20210331152757963.png]

v.insert(++v.begin(), s2.begin(), s2.end());	//在第二个元素的位置插入s2的整个字符串

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 7]

## 5.erase ##

### 1)删除对应位置的字符 ###

![在这里插入图片描述][20210331154214166.png]

string s("abcdef");
    	vector<char>v(s.begin(), s.end());	
    
    	v.erase(v.begin());		//删除首元素

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NjU1NDU4Mg_size_16_color_FFFFFF_t_70 8]

### 2)删除范围内的字符串 ###

![在这里插入图片描述][20210331154224844.png]

v.erase(++v.begin(), --v.end());	//删除第二个元素到倒数第二个元素之间的所有元素

![在这里插入图片描述][20210331155017306.png]  
这就是对于内部功能的简单实现,当然还有一个对应的emplace函数,我在下一篇单独写出来

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