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：

1. 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;

}

2：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;

}

 

 

转载自 jihite