map iterator c++ code example

Example 1: how to iterate through a map in c++

//traditional way (long)
for(map<string,int>::iterator it=m.begin(); it!=m.end(); ++it)
	if(it->second)cout<<it->first<<" ";
//easy way(short) just works with c++11 or later versions
for(auto &x:m)
	if(x.second)cout<<x.first<<" ";
//condition is just an example of use

Example 2: c++ map iterator

#include <iostream>
#include <map>
 
int main() {
  std::map<int, float> num_map;
  // calls a_map.begin() and a_map.end()
  for (auto it = num_map.begin(); it != num_map.end(); ++it) {
    std::cout << it->first << ", " << it->second << '\n';
  }
}

Example 3: iterar un map c++

//traditional way (long)
for(map<string,int>::iterator it=m.begin(); it!=m.end(); ++it)
	if(it->second)cout<<it->first<<" ";
//easy way(short) just works with c++11 or later versions
for(auto &x:m)
	if(x.second)cout<<x.first<<" ";
//condition is just an example of use

Example 4: map in c++

#include <bits/stdc++.h>
#include <iostream>
#include <map>
using namespace std;
void mapDemo(){
	map<int, int> A;
	A[1] = 100;
	A[2] = -1;
	A[3] = 200;
	A[100000232] = 1;
	//to find the value of a key
	//A.find(key)
	
	//to delete the key
	//A.erase(key)
	
	map<char, int> cnt;
	string x = "Sumant Tirkey";
	
	for(char c:x){
		cnt[c]++;//map the individual character with it's occurance_Xtimes
	}
	
	//see  how many times a and z occures in my name
	cout<< cnt['a']<<" "<<cnt['z']<<endl;
	
} 
	
int main() {
	mapDemo();
	return 0;
}