maps 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;
}
#include <iostream>
#include <iterator>
#include <map>
using namespace std;
int main()
{
// empty map container
map<int, int> gquiz1;
// insert elements in random order
gquiz1.insert(pair<int, int>(1, 40));
gquiz1.insert(pair<int, int>(2, 30));
gquiz1.insert(pair<int, int>(3, 60));
gquiz1.insert(pair<int, int>(4, 20));
gquiz1.insert(pair<int, int>(5, 50));
gquiz1.insert(pair<int, int>(6, 50));
gquiz1.insert(pair<int, int>(7, 10));
// printing map gquiz1
map<int, int>::iterator itr;
cout << "\nThe map gquiz1 is : \n";
cout << "\tKEY\tELEMENT\n";
for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
cout << endl;
// assigning the elements from gquiz1 to gquiz2
map<int, int> gquiz2(gquiz1.begin(), gquiz1.end());
// print all elements of the map gquiz2
cout << "\nThe map gquiz2 after"
<< " assign from gquiz1 is : \n";
cout << "\tKEY\tELEMENT\n";
for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
cout << endl;
// remove all elements up to
// element with key=3 in gquiz2
cout << "\ngquiz2 after removal of"
" elements less than key=3 : \n";
cout << "\tKEY\tELEMENT\n";
gquiz2.erase(gquiz2.begin(), gquiz2.find(3));
for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
// remove all elements with key = 4
int num;
num = gquiz2.erase(4);
cout << "\ngquiz2.erase(4) : ";
cout << num << " removed \n";
cout << "\tKEY\tELEMENT\n";
for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
cout << '\t' << itr->first
<< '\t' << itr->second << '\n';
}
cout << endl;
// lower bound and upper bound for map gquiz1 key = 5
cout << "gquiz1.lower_bound(5) : "
<< "\tKEY = ";
cout << gquiz1.lower_bound(5)->first << '\t';
cout << "\tELEMENT = "
<< gquiz1.lower_bound(5)->second << endl;
cout << "gquiz1.upper_bound(5) : "
<< "\tKEY = ";
cout << gquiz1.upper_bound(5)->first << '\t';
cout << "\tELEMENT = "
<< gquiz1.upper_bound(5)->second << endl;
return 0;
}
#include <iostream>
#include <string>
#include <map>
using std::string;
using std::map;
int main() {
// A new map
map<string, int> myMap {
{"one", 1},
{"two", 2},
{"three", 3}
};
// Print map contents (C++11 or higher)
for (auto& iter: myMap) {
std::cout << iter.first << ": " << iter.second << std::endl;
}
}
#include <iostream>
#include <iterator>
#include <map>
using namespace std;
int main()
{
map<int, int> marks;
marks.insert(pair<int, int>(160, 42));
marks.insert(pair<int, int>(161, 30));
marks.insert(pair<int, int>(162, 40));
marks.insert(pair<int, int>(163, 50));
marks.insert(pair<int, int>(164, 31));
marks.insert(pair<int, int>(165, 12));
marks.insert(pair<int, int>(166, 34));
map<int, int>::iterator itr;
cout << "nThe map marks is : n";
cout << "ROLL NO.tMarksn";
for (itr = marks.begin(); itr != marks.end(); ++itr) {
cout << itr->first
<< "t t" << itr->second << 'n';
}
cout << endl;
return 0;
}
