C++中的std :: 字符串:: erase

该函数删除了一部分字符串内容，从而缩短了字符串的长度。受影响的字符取决于所使用的成员函数版本：
返回值： Erase()返回* this。

1. 语法1：删除字符串的所有字符

string& string ::erase ()

CPP

// CPP code to illustrate
// erase() function
 
#include 
#include 
using namespace std;
 
// Function to demo erase()
void eraseDemo(string str)
{
    // Deletes all characters
    str.erase();
 
    cout << "After erase() : ";
    cout << str;
}
 
// Driver code
int main()
{
    string str("Hello World!");
 
    cout << "Before erase() : ";
    cout << str << endl;
    eraseDemo(str);
 
    return 0;
}

输出：

Before erase() : Hello World!
After erase() : 

2.语法2：删除位置“ pos”之后的所有字符

string& string ::erase (size_type pos)
- Throw out_of_range if idx > size().

CPP

// CPP code to illustrate working of
// erase(idx)
 
#include 
#include 
using namespace std;
 
// Function to demo erase
void eraseDemo(string str)
{
    // Deletes all characters except first one
    str.erase(1);
 
    cout << "After erase(idx) : ";
    cout << str;
}
 
// Driver code
int main()
{
    string str("Hello World!");
 
    cout << "Before erase(idx) : ";
    cout << str << endl;
    eraseDemo(str);
 
    return 0;
}

输出：

Before erase(idx) : Hello World!
After erase(idx) : H

3.语法3：从索引idx开始，最多擦除* this的len个字符。

string& string ::erase (size_type idx, size_type len )
- If len is missing, all remaining characters are removed.
- Throw out_of_range if idx > size().

CPP

// CPP code to illustrate
// erase(size_type idx, size_type len )
#include 
#include 
using namespace std;
 
// Function to demo erase
void eraseDemo(string str)
{
    // Deletes 4 characters from index number 1
    str.erase(1, 4);
 
    cout << "After erase : ";
    cout << str;
}
 
// Driver code
int main()
{
    string str("Hello World!");
 
    cout << "Before erase : ";
    cout << str << endl;
    eraseDemo(str);
 
    return 0;
}

输出：

Before erase : Hello World!
After erase : H World!

4.语法4：擦除迭代器位置pos处的单个字符。

string& string ::erase (iterator pos)
- Return the first character after the last character removed
- If no such character is remaining then, returns 
  string::end() i.e. position after the last character.

CPP

// CPP code to illustrate
// erase(iterator pos)
 
#include 
#include 
using namespace std;
 
// Function to demo erase
void eraseDemo(string str)
{
    // Deletes character at position 4
    str.erase(str.begin() + 4);
 
    cout << "After erase : ";
    cout << str;
}
 
// Driver code
int main()
{
    string str("Hello World!");
 
    cout << "Before erase : ";
    cout << str << endl;
    eraseDemo(str);
 
    return 0;
}

输出：

Before erase : Hello World!
After erase : Hell World!

5.语法5：删除迭代器pos中的字符。到另一个迭代器pos。

string& string ::erase (iterator beg, iterator end )
- Erases all characters of the range [ beg, end)
- Returns end i.e. the first character after the
  last character removed.
- If no such character is remaining then, returns 
  string::end() i.e. position after the last character

CPP

// CPP code to illustrate
// erase(iterator pos, iterator end)
 
#include 
#include 
using namespace std;
 
// Function to demo erase
void eraseDemo(string str)
{
    // Deletes all characters between 0th index and
    // str.end() - 6
    str.erase(str.begin() + 0, str.end() - 6);
 
    cout << "After erase : ";
    cout << str;
}
 
// Driver code
int main()
{
    string str("Hello World!");
 
    cout << "Before erase : ";
    cout << str << endl;
    eraseDemo(str);
 
    return 0;
}

输出：

Before erase : Hello World!
After erase : World!

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