代码如下:
#include <iostream>
#include <string>
#include <map>
using namespace std;void printMap(map<int,int>&m)
{for (map<int, int>::iterator it = m.begin(); it != m.end(); it++){cout << "key = " << it->first << "value = " << it->second << endl;}cout << endl;
}void test01()
{map<int, int>m;m.insert(pair<int, int>(1, 10));m.insert(pair<int, int>(2, 20));m.insert(pair<int, int>(3, 30));m.insert(pair<int, int>(4, 40));printMap(m);map<int, int>m2(m);printMap(m2);map<int, int>m3;m3 = m2;printMap(m3);
}int main()
{test01();return 0;
}
测试结果:
总结:
map中所有元素都是成对出现,插入数据时候要使用对组。
代码如下:
#include <iostream>
#include <string>
#include <map>
using namespace std;void printMap(map<int,int>&m)
{for (map<int, int>::iterator it = m.begin(); it != m.end(); it++){cout << "key = " << it->first << "value = " << it->second << endl;}cout << endl;
}void test01()
{map<int, int>m;m.insert(pair<int, int>(1, 10));m.insert(pair<int, int>(2, 20));m.insert(pair<int, int>(3, 30));m.insert(pair<int, int>(4, 40));if (m.empty()){cout << "m empty" << endl;}else{cout << "m no empty" << endl;cout << "m size = " << m.size() << endl;}map<int, int>m2;m2.insert(pair<int, int>(4, 100));m2.insert(pair<int, int>(5, 200));m2.insert(pair<int, int>(6, 300));cout << "交换前" << endl;printMap(m);printMap(m2);cout << "交换后" << endl;printMap(m);printMap(m2);}int main()
{test01();return 0;
}
测试结果:
总结:
代码如下:
#include <iostream>
#include <string>
#include <map>
using namespace std;void printMap(map<int,int>&m)
{for (map<int, int>::iterator it = m.begin(); it != m.end(); it++){cout << "key = " << it->first << "value = " << it->second << endl;}cout << endl;
}void test01()
{map<int, int>m;m.insert(pair<int, int>(1, 10));m.insert(make_pair(2, 20));m.insert(map<int, int>::value_type(3, 30));m[4] = 40;printMap(m);m.erase(m.begin());printMap(m);m.erase(3);printMap(m);m.erase(m.begin(), m.end());m.clear();printMap(m);}int main()
{test01();return 0;
}
测试结果:
总结:
代码如下:
#include <iostream>
#include <string>
#include <map>
using namespace std;void printMap(map<int,int>&m)
{for (map<int, int>::iterator it = m.begin(); it != m.end(); it++){cout << "key = " << it->first << "value = " << it->second << endl;}cout << endl;
}void test01()
{map<int, int>m;m.insert(pair<int, int>(1, 10));m.insert(pair<int, int>(2, 20));m.insert(pair<int, int>(3, 30));m.insert(pair<int, int>(4, 40));map<int, int>::iterator pos = m.find(3);if (pos != m.end()){cout << "find key = " << (*pos).first << "value = " << (*pos).second << endl;}else{cout << "no find" << endl;}int num = m.count(3);cout << "num = " << num << endl;}int main()
{test01();return 0;
}
测试结果:
总结:
代码如下:
#include <iostream>
#include <string>
#include <map>
using namespace std;void printMap(map<int,int>&m)
{for (map<int, int>::iterator it = m.begin(); it != m.end(); it++){cout << "key = " << it->first << "value = " << it->second << endl;}cout << endl;
}class cmp
{
public:bool operator()(int a, int b){return a > b;}
};void test01()
{map<int, int, cmp>m;m.insert(make_pair(1, 10));m.insert(make_pair(2, 20));m.insert(make_pair(3, 30));m.insert(make_pair(4, 40));m.insert(make_pair(5, 50));for (map<int, int, cmp>::iterator it = m.begin(); it != m.end(); it++){cout << "key = " << it->first << "value = " << it->second << endl;}}int main()
{test01();return 0;
}
测试结果:
总结: