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c++ map

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programmatoroSeduto answered on August 19, 2020 Popularity 10/10 Helpfulness 3/10

answer c++ map

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c++ map

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#include <map>

// ===== CONSTRUCTOR

// map (char -> int)
std::map<char,int> map_int;
map_int['a']=10;
map_int['b']=30;

// map (int -> string)
std::map<int, std::string> map_string;
map_string[24] = "46";

// ===== EXISTENCE and SIZE

// map size
map_int.size() : size_type (int)

// search for 'a'
// map.find(key) : map.iterator
if(map_int.find('a') != map_int.end()) {/*...*/}
// map_iterator->first : type(key)
// map_iterator->second : type(value)

// check if the map is empty
map_int.empty() // : bool

// ===== SET

// just name and set 
// if the element already exists, the statement will override that value
map_int['a']=10;

// check before set
if(map_int.find('a') == map_int.end()) 
	map_int['a']=10;

// ===== DELETE

// first: iterator, then: erase(it)
auto it = map_int.find('a');
if(it != map_int.end())
	map_int.erase(it);

// or also, using keys
map_int.erase('a');

Popularity 10/10 Helpfulness 3/10 Language cpp

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Tags: c++ map

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Contributed on Jul 31 2022

programmatoroSeduto

0 Answers Avg Quality 2/10

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map in cpp

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#include <map>

// empty map container 
map<int, int> gquiz1; 
  
// insert elements in random order 
gquiz1.insert(pair<int, int>(1, 40));

Popularity 10/10 Helpfulness 3/10 Language cpp

Source: Grepper

Tags: c++

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Contributed on Oct 01 2020

Alert Ant

0 Answers Avg Quality 2/10

map in cpp

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#include <map>

int main(){
  //new map
  std::map <int,int> myMap;
  myMap[0] = 1;
  myMap[1] = 2;
  myMap[2] = 3;
  myMap[3] = 4;
}

Popularity 10/10 Helpfulness 3/10 Language cpp

Source: Grepper

Tags: c++

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Contributed on Nov 11 2020

Zany Zebra

0 Answers Avg Quality 2/10

Map example cpp

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#include <iostream>
#include <map>
using namespace std;
int main(){
    map <char,int> mp;
    map <char,int> mymap,mymap1;

    //insert elements individually in map with the combination of key value and value of element
    mp.insert(pair<char,int>('a',2));   //key is 'c' and 2 is value.
    mp.insert(pair<char,int>('b',1));
    mp.insert(pair<char,int>('c',43));

    //inserts elements in range using insert() function in map 'mymap'.
    mymap.insert(mp.begin(),mp.end());

    //declaring iterator for map
    map <char,int>::iterator it;

    //using find() function to return reference of element mapped by key 'b'.
    it = mp.find('b');

    //prints key and element's value.
    cout<<"Key and element's value of map are: ";
    cout<<it->first<<" and "<<it->second<<endl;

    //alternative way to insert elements by mapping with their keys.
    mymap1['x'] = 23;
    mymap1['y'] = 21;

    cout<<"Printing element mapped by key 'b' using at() function : "<<mp.at('b')<<endl;

    //swap contents of 2 maps namely mymap and mymap1.
    mymap.swap(mymap1);

    /* prints swapped elements of mymap and mymap1 by iterating all the elements through    
        using   iterator. */
    cout<<"Swapped elements and their keys of mymap are: "<<endl;
    for(it=mymap.begin();it!=mymap.end();it++)
    {
    cout<<it->first<<" "<<it->second<<endl;
    }
    cout<<"Swapped elements and their keys of mymap1 are: "<<endl;
    for(it=mymap1.begin();it!=mymap1.end();it++)
    {
    cout<<it->first<<" "<<it->second<<endl;
    }
    //erases element mapped at 'c'.
    mymap1.erase('c');

    //prints all elements of mymap after erasing element at 'c'.

    cout<<"Elements of mymap1 after erasing element at key 'c' : "<<endl;
    for(it=mymap1.begin();it!=mymap1.end();it++)
    {
    cout<<it->first<<" "<<it->second<<endl;
    }

    //erases elements in range from mymap1
    mymap1.erase(mymap1.begin(),mymap1.end());

    cout<<"As mymap1 is empty so empty() function will return 1 : " << mymap1.empty()<<endl;

    //number of elements with key = 'a' in map mp.
    cout<<"Number of elements with key = 'a' in map mp are : "<<mp.count('a')<<endl;

    //if mp is empty then itmp.empty will return 1 else 0.
    if(mp.empty())
    {
        cout<<"Map is empty"<<endl;
    }
    else
    {
        cout<<"Map is not empty"<<endl;
    }

    return 0;
}

Popularity 9/10 Helpfulness 2/10 Language cpp

Source: www.hackerearth.com

Tags: c++

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Contributed on Dec 26 2023

Distinct Dugong

0 Answers Avg Quality 2/10

c++ map

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#include <iostream>
#include <string>
#include <map>

using std::string;
using std::map;
map <int,string>MapName;//you can put type you want
map<int,string>::iterator iter;

int main(){
 	int i=31136;
  	string s="name;
//How you insert values
	MapName.insert(pair<int,string>(i,s));
//How you print keys and values 
  	for(iter=studentId.begin();iter!=studentId.end();iter++){
    	cout<<"Key"<<iter->first<<"Value: "<<iter->second<<endl;
    	}
//How you search data
  	if (m.find(31136) != m.end()) {
		cout << "found" << endl;
		}
	else {
		cout << "not found" << endl;
		}
	}

Popularity 10/10 Helpfulness 2/10 Language cpp

Source: Grepper

Tags: c++

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Contributed on May 29 2022

Dull Dolphin

0 Answers Avg Quality 2/10

map of maps c++

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map <typename,map<typename,typename>> mp;
map[key1][key2]=values

Popularity 10/10 Helpfulness 1/10 Language cpp

Source: Grepper

Tags: c++

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Contributed on Aug 19 2020

Hilarious Hyena

0 Answers Avg Quality 2/10

map in c++

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map in c++

std::map<key_type, value_type> map_name = {{key1, value1},{key2, value2}, ...};

if {1,1,1,2,2,3,3,3,3,4} then after operation for key1 = 4 value will be 1

Popularity 10/10 Helpfulness 1/10 Language cpp

Source: www.programiz.com

Tags: c++

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Contributed on Jul 03 2023

Scary Shark

0 Answers Avg Quality 2/10

c++ map

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