Associative arrays in C++

Last Updated : 09 Feb, 2022

Associative arrays are also called map or dictionaries. In C++. These are special kind of arrays, where indexing can be numeric or any other data type
i.e can be numeric 0, 1, 2, 3.. OR character a, b, c, d… OR string geek, computers…
These indexes are referred as keys and data stored at that position is called
value.
So in associative array we have (key, value) pair.
We use STL maps to implement the concept of associative arrays in C++.

Example:
Now we have to print the marks of computer geeks whose names and marks are as follows

  Name        Marks
       Jessie       100
       Suraj        91
       Praveen      99   
       Bisa         78
       Rithvik      84

CPP

// CPP program to demonstrate associative arrays
#include <bits/stdc++.h>
using namespace std;
int main()
{
    // the first data type i.e string represents 
    // the type of key we want the second data type
    // i.e int represents the type of values we 
    // want to store at that location
    map<string, int> marks{ { "Rithvik", 78 },
            { "Suraj", 91 }, { "Jessie", 100 },
            { "Praveen", 99 }, { "Bisa", 84 } };
 
     map<string, int>::iterator i; 
    cout << "The marks of all students are" << endl;
    for (i = marks.begin(); i != marks.end(); i++) 
        cout << i->second << " ";
     
 
    cout << endl;
 
    // the marks of the students based on there names.
    cout << "the marks of Computer geek Jessie are"
         << " " << marks["Jessie"] << endl; 
 
    cout << "the marks of geeksforgeeks contributor"
          " Praveen are " << marks["Praveen"] << endl;
}

Output:

The marks of all students are
84 100 99 78 91 
the marks of Computer geek Jessie are 100
the marks of geeksforgeeks

 Praveen are 99

S

SrjSunny

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array::at() in C++ STL

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