STL容器 string-优快云博客

本文链接：https://blog.youkuaiyun.com/m0_52095916/article/details/126664871

本文详细介绍了C++中string类的各种构造函数、赋值操作、字符串拼接、查找与替换、字符串比较、字符存取、插入与删除以及子串获取的方法，通过实例展示了每个操作的使用方式，帮助读者深入理解C++中字符串处理的常用技巧。

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1.string的构造函数

#include <iostream>
using namespace std;

//string的构造函数
//string(); string(const char*s);
//string(const char& str); string(int n,char c);
void test01()
{
	string s1;//默认构造

	const char* str = "hello world";
	string s2(str);
	cout << s2 << endl;

	string s3(s2);//拷贝构造
	cout << s3 << endl;

	string s4(10, 'a');
	cout << s4 << endl;
}

int main()
{
	test01();
}

2.string赋值操作

#include <iostream>
using namespace std;
//string的赋值操作
/*
	string& operator=(const char* s);
	string& operator=(const string &s);
	string& operator=(char c);
	string& assign(const char* s);
	string& assign(const char* s,int n);
	string& assign(const string &s);
	string& assign(int n,char c);
*/

void test01()
{
	string str1;
	str1= "hello world";;
	cout << str1 << endl;

	string str2;
	str2= str1;
	cout << str2 << endl;
	
	string str3;
	str3 = 'a';
	cout << str3 << endl;

	string str4;
	str4.assign("hello");
	cout << str4 << endl;

	string str5;//前n个字符
	str5.assign("hello",1);
	cout << str5 << endl;

	string str6;
	str6.assign(str5);
	cout << str6 << endl;

	string str7;
	str7.assign(5,'a');
	cout << str7 << endl;
}

int main()
{
	test01();
}

3.string字符串拼接

#include <iostream>
using namespace std;
//string的拼接操作

void test01()
{
	string str1 = "我";
	str1 += "爱玩游戏";
	str1 += ':';
	cout << str1 << endl;
	string str2 = "王者荣耀";
	str1 += str2;
	cout << str1 << endl;

	string str3 = "I";
	str3.append("love ");
	str3.append("王者荣耀", 2);
	cout << str3 << endl;

	str3.append(str2);
	cout << str3 << endl;

	str3.append(str2,2,7);
	cout << str3 << endl;
}
int main()
{
	test01();
}

4.string查找和替换

#include <iostream>
using namespace std;
//string的查找替换操作

void test01()
{
	string str1 = "abcdefgde";
	int pos = str1.find("de");//从左往右查  从0开始
	int re= str1.rfind("de");//从左往右查
	cout << pos << endl;
	cout << re<< endl;
}

void test02()
{
	string str1 = "abcdef";
	str1.replace(1, 3, "1111");//bcd替换成1111
	cout << str1 << endl;
}

int main()
{
	test01();
	test02();
}

5.string 的字符串比较

#include <iostream>
using namespace std;
//string的字符串比较操作
//比较方式：字符的ASCII码
/*
	=返回0
	>返回1
	<返回-1
*/

void test01()
{
	string str1 = "hallo";
	string str2 = "hello";
	int flag = str1.compare(str2);
	cout << flag << endl;
}

int main()
{
	test01();
}

6.string 字符存取

#include <iostream>
using namespace std;
//string的字符存取

void test01()
{
	string str1 = "hello";

	//通过[]访问单个字符
	for (int i = 0; i < str1.size(); i++)
	{
		cout << str1[i] << " ";
	}
	cout << endl;
	//通过at方式访问单个字符
	for (int i = 0; i < str1.size(); i++)
	{
		cout << str1.at(i) << " ";
	}
	cout << endl;
	str1[0] = 'a';
	str1.at(3) = 'b';
	cout << str1;
}

int main()
{
	test01();
}

7.string字符串插入和删除

#include <iostream>
using namespace std;
//string的字符串插入和删除

void test01()
{
	string str1 = "hello";

	str1.insert(1, "111");//插入后为h111ello
	cout << str1 << endl;

	str1.erase(1, 3);//删除插入的111
	cout << str1 << endl;
}
int main()
{
	test01();
}

8.string字串获取

#include <iostream>
using namespace std;
//string子串获取

void test01()
{
	string str = "abcdef";
	string sustr = str.substr(0, 3);//从第0个获取三个字符
	cout << sustr << endl;;
}
int main()
{
	test01();
}