File System, C++ (gcc)

File System

/* File System
Write a file system class, which has two functions: create, and get

create("/a",1)
get("/a") //get 1
create("/a/b",2)
get("/a/b") //get 2
create("/c/d",1) //Error, because "/c" is not existed
get("/c") //Error, because "/c" is not existed */

#include <iostream>
#include <map>
#include <string>
#include <assert.h>

using namespace std;

class Runable{
};

class FileSystem{
    map<string,int> m; // path, val
    map<string, Runable> callbackMap; // path, runable
public:
    bool create(string path, int val){
        //remove the last '/'
        if(path.back() == '/') path.pop_back();

//itself should not already exist
        if(m.count(path)) return false;

//parent should exist
        int pos = path.find_last_of('/');
        if(pos){
            string parent = path.substr(0, pos);
            if(m.count(parent) == 0) return false;
        }
        m[path] = val;
        return true;
    }

int get(string path){
        if(m.count(path) == 0)
            return -1;
        return m[path];
    }

bool set(string path, int val){
        if(m.count(path) == 0)
            return false;
        m[path] = val;
        return true;
    }

bool watch(string path, Runable running){
        if(m.count(path) == 0) return false;
        callbackMap[path] = running;
        return true;
    }

};

int main() {
    FileSystem fs;

bool res1  = fs.create("/a",1);
    bool res2 = fs.create("/a/b", 2);
    bool res3 = fs.create("/c/d",1);

assert(res1 == true);
    assert(res2 == true);
    assert(res3 == false);

int v1 = fs.get("/a");  //get 1
    int v2 = fs.get("/a/b");  //get 2
    int v3 = fs.get("/c");
    assert(v1 == 1);
    assert(v2 == 2);
    assert(v3 == -1);

Runable x; // watching
    bool rx = fs.watch("/a", x);
    assert(rx == true);

cout << endl <<  "All pass !" << endl << endl;
    return 0;
}


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