c++一些常用函数的积累

string

// string::substr
#include <iostream>
#include <string>

int main ()
{
  std::string str="We think in generalities, but we live in details.";
                                           // (quoting Alfred N. Whitehead)

  std::string str2 = str.substr (3,5);     // "think"

  std::size_t pos = str.find("live");      // position of "live" in str 

  std::string str3 = str.substr (pos);     // get from "live" to the end

  std::cout << str2 << ' ' << str3 << '\n';

  return 0;
}
//Output:
//think live in details.

#include <string>
#include <iostream>
#include<vector>
#include<map>
using namespace std;

int main(){
    string temp;
    vector<string> ans;
    map<string, string> dic;
    /*dic["a"] = "aa";
    dic["b"] = "bb";
    for (auto s : dic)
    cout << s.second << endl;*/
    int m, n;
    cin >> m >> n;
    int a = m + n+1;
    while (a--){
        getline(cin, temp);
        if (!temp.size()) continue;
        if (temp[0] == '<')
            ans.push_back(temp);
        else{
            int pos = temp.find(" ");
            string signal = "{{ " + temp.substr(0, pos) + " }}";
            string val = temp.substr(pos + 2, temp.size() - pos - 3);
            dic[signal] = val;
        }
    }
    for (int i; i < ans.size();i++){
        for (map<string, string>::iterator it = dic.begin(); it != dic.end();it++){
            int pos;
            while ((pos = ans[i].find(it->first)) != string::npos){
                ans[i].replace(pos, it->first.size(), it->second);
            }
        }
    }
    //cout << ans[0] << endl;
    for (int i = 0; i < ans.size();i++)
        cout << ans[i]<< endl;
    system("pause");
    return 0;
}

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来源：https://www.cnblogs.com/fridge/p/4861903.html