[C++STL]map容器用法介绍
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[C++STL]map容器用法介绍
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代碼如下:
#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; }測(cè)試結(jié)果:
總結(jié):
map中所有元素都是成對(duì)出現(xiàn),插入數(shù)據(jù)時(shí)候要使用對(duì)組。
代碼如下:
#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 << "交換前" << endl;printMap(m);printMap(m2);cout << "交換后" << endl;printMap(m);printMap(m2);}int main() {test01();return 0; }測(cè)試結(jié)果:
總結(jié):
代碼如下:
#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; }測(cè)試結(jié)果:
總結(jié):
代碼如下:
#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; }測(cè)試結(jié)果:
總結(jié):
代碼如下:
#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; }測(cè)試結(jié)果:
總結(jié):
總結(jié)
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