practical_exercises/key_exercises/map_insert_look.cpp - master - githubmirror/CPlusPlusThings

practical_exercises/key_exercises/map_insert_look.cpp
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zhangxing
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30 мар 2024, 17:00
30 мар 2024, 17:003c8a3f2
/* 字典插入与查找.cpp */
#include <cstring>
#include <iostream>
#include <map>
using namespace std;

int main(int argc, char const *argv[]) {
  map<const char *, const char *> mp;
  map<const char *, const char *>::iterator iter;
  const char key[3][20] = {"img", "system", "ip"};
  const char value[3][20] = {"d:/a.img", "win7", "193.68.6.3"};

  // make_pair插入
  for (int i = 0; i < 2; i++) {
    mp.insert(make_pair(key[i], value[i]));
  }
  // pair<const char*,const char*>插入
  mp.insert(pair<const char *, const char *>(key[2], value[2]));

  //数组插入方式
  mp["addr"] = "中国";
  //迭代器取出元素
  //循环取出元素
  for (iter = mp.begin(); iter != mp.end(); iter++) {
    cout << iter->first << "\t" << iter->second << endl;
  }
  char key1[20];
  cout << "请输入按key查找：";
  cin.getline(key1, 20);
  //查找元素
  for (iter = mp.begin(); iter != mp.end(); iter++) {
    if (strcmp(iter->first, key1) == 0) {
      cout << iter->first << "查找出来了！"
           << "对应的值为：" << iter->second << endl;
    }
  }

  //第一种删除方式
  // find只能用于查找数组建立的形式！并且不支持输入用cin等
  iter = mp.find("addr");
  if (iter != mp.end()) {
    cout << iter->first << "按照key查找出来了！"
         << "对应的value为：" << iter->second << endl;
    cout << "开始删除元素！" << endl;
    mp.erase(iter);
    // break;
  }
  //第二种方式删除
  //按照key删除元素
  char drop_key[20];
  //按照value删除元素
  char drop_value[20];
  cout << "请输入按key删除：";
  cin.getline(drop_key, 20);
  cout << "请输入按value删除：";
  cin.getline(drop_value, 20);
  for (iter = mp.begin(); iter != mp.end(); iter++) {
    if (strcmp(iter->first, drop_key) == 0) {
      cout << iter->first << "按照key查找出来了！"
           << "对应的value为：" << iter->second << endl;
      cout << "开始删除元素！" << endl;
      mp.erase(iter);
      break;
    }
    if (strcmp(iter->second, drop_value) == 0) {
      cout << iter->second << "value查找出来了！"
           << "对应的key为：" << iter->first << endl;
      cout << "开始删除元素！" << endl;
      mp.erase(iter);
      break;
    }
  }
  cout << "------删除元素以后--------\n";
  //循环取出元素
  for (iter = mp.begin(); iter != mp.end(); iter++) {
    cout << iter->first << "\t" << iter->second << endl;
  }
  
  return 0;
}