string

获取一整行

#include<bits/stdc++.h>
using namespace std;
stack<int> t;
int main(){
	int n;
	cin >> n;
	string s;
	getchar();
	getline(cin,s);
	cout << n << endl;
	cout << s << endl;
	
	return 0;
}

查找

#include<bits/stdc++.h>
using namespace std;
stack<int> t;
int main(){
	string s;
	s = "hello world"; //增删改查 
	//查找find  
	int k = s.find("lk");
	if(k!=-1){
		cout << "YES\n";
	}else{
		cout << "NO\n";
	}
	if(s.find("llo")!=string::npos){//string::npos : s.npos
		cout << "YES\n";
	}else{
		cout << "NO\n";
	}
	s = "hello world";
	if(s.find("llo",5)!=string::npos){//从下标5开始找 
		cout << "YES\n";
	}else{
		cout << "NO\n";
	}
	return 0;
}

删除

#include<bits/stdc++.h>
using namespace std;
stack<int> t;
int main(){
	string s;
	s = "hello world"; //增删改查 
	//删除
	s.erase(2,3);
	cout << s << endl;
	
	return 0;
}

更换

#include<bits/stdc++.h>
using namespace std;
stack<int> t;
int main(){
	string s;
	s = "hello world"; //增删改查 
	//修改，更替
	s.replace(1,4,"i");
	cout << s;
	
	return 0;
}

插入

#include<bits/stdc++.h>
using namespace std;
stack<int> t;
int main(){
	string s;
	s = "hello world"; //增删改查 
	//插入insert 
	s.insert(3,"abc");//在下标3的前面插入“abc” 
	cout << s;
	return 0;
}

截取

#include<bits/stdc++.h>
using namespace std;
stack<int> t;
int main(){
	string s;
	s = "hello world"; //增删改查 
	//截取
	string ss = s.substr(2,6) ;
	cout << s << endl;
	cout << ss << endl;
	return 0;
}