Frequency Counter Pattern Using Hash Map in DSA C - Build from Scratch

Frequency Counter Pattern Using Hash Map

📖 Scenario: You are working in a small grocery store. You want to count how many times each fruit appears in a list of fruits sold today.

🎯 Goal: Build a program that counts the frequency of each fruit sold using a hash map (dictionary) and prints the counts.

📋 What You'll Learn

Create an array of fruits with exact values

Create a hash map (dictionary) to store fruit counts

Use a loop to count the frequency of each fruit

Print the frequency of each fruit in the format: fruit: count

💡 Why This Matters

🌍 Real World

Counting frequencies is useful in stores to track sales, in text analysis to count words, and in many other data processing tasks.

💼 Career

Understanding frequency counting with hash maps is a key skill for software developers, data analysts, and anyone working with data structures.

1

Create the list of fruits sold

Create a char* array called fruits with these exact values: "apple", "banana", "apple", "orange", "banana", "apple".

DSA C

# Create the array fruits with the given fruit names
// Your code here

Hint

Use an array of char* strings and count the number of fruits in a separate variable.

2

Set up the hash map for counting

Create a struct called FruitCount with two fields: char* fruit and int count. Then create an array called counts of size 3 to store FruitCount elements. Initialize all count fields to 0.

DSA C

#include 

// Define struct FruitCount and create counts array
// Your code here

Hint

Use a struct to hold fruit name and count. Initialize counts for each fruit to zero.

3

Count the frequency of each fruit

Write a for loop with variable i from 0 to fruits_count - 1. Inside it, write another for loop with variable j from 0 to 2 to compare fruits[i] with counts[j].fruit using strcmp. If they match, increase counts[j].count by 1.

DSA C

// Count the frequency of each fruit
// Your code here

Hint

Use nested loops and strcmp to compare strings and update counts.

4

Print the frequency of each fruit

Write a for loop with variable k from 0 to 2. Inside the loop, print the fruit and its count in the format: fruit: count using printf.

DSA C

// Print the frequency of each fruit
// Your code here

Hint

Use a loop and printf to display each fruit and its count on a new line.