C++ find 函数用法

头文件

#include <algorithm>

函数实现

template<class InputIterator, class T>
InputIterator find (InputIterator first, InputIterator last, const T& val)
{
  while (first!=last) 
  {
     if (*first==val) return first;
     ++first;
   }
    return last;
}

举例

1. vector

   #include <iostream>
   #include <algorithm>
   #include <vector>
   using namespace std;
   
   int main()
   {
       vector<string> m;
       m.push_back("hello");
       m.push_back("hello2");
       m.push_back("hello3");
       if (find(m.begin(), m.end(), "hello") == m.end())
           cout << "no" << endl;
       else
           cout << "yes" << endl;
   }

2. set

   #include <iostream>
   #include <algorithm>
   #include <string>
   #include <set>
   using namespace std;
   
   int main()
   {
       set<string> m;
       m.insert("hello");
       m.insert("hello2");
       m.insert("hello3");
       if (find(m.begin(), m.end(), "hello") == m.end())
           cout << "no" << endl;
       else
           cout << "yes" << endl;
   }

注意：

set自身有个find函数，举例如下：

#include <iostream>
#include <algorithm>
#include <string>
#include <set>
using namespace std;

int main()
{
    set<string> m;
    m.insert("hello");
    m.insert("hello2");
    m.insert("hello3");
    if (find(m.begin(), m.end(), "hello") == m.end())
        cout << "no" << endl;
    else
        cout << "yes" << endl;
}

string自身有个find函数，举例如下：

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

int main()
{
    string s = "helllo";
    if (s.find("e") == string::npos)  //yes
        cout << "no" << endl;
    else
        cout << "yes" << endl;

    if (s.find("z") == string::npos)  //no
        cout << "no" << endl;
    else
        cout << "yes" << endl;
}