C program to find the frequency of characters in a string Last Updated : 01 Jun, 2023 Comments Improve Suggest changes Like Article Like Report Given a string S containing lowercase English characters, the task is to find the frequency of all the characters in the string. ExamplesInput: S="geeksforgeeks" Output: e - 4 f - 1 g - 2 k - 2 o - 1 r - 1 s - 2 Input: S="gfg" Output: f - 1 g - 2Approach Follow the steps to solve the problem: Initialize an array freq[] to store the frequency of each alphabet in the given string. The 0th index stores the frequency of the character 'a', the 1st index stores the frequency of the character 'b', and so on.Iterate over the given string S and increment the frequency of each character encountered by 1, by performing freq[S[i] - 'a'] += 1. If S[i] = 'a', then S[i] - 'a' is equal to 0, therefore the frequency of 'a' is incremented in the array.After complete traversal of the string, print the frequency of all the characters in the string by traversing the array freq[]. Below is the implementation of the above approach: C // C program to find the frequency // of characters in a string #include <stdio.h> #include <string.h> // Function to print the frequencies // of each character of the string void printFrequency(int freq[]) { for (int i = 0; i < 26; i++) { // If frequency of the // alphabet is non-zero if (freq[i] != 0) { // Print the character and // its respective frequency printf("%c - %d\n", i + 'a', freq[i]); } } } // Function to calculate the frequencies // of each character of the string void findFrequncy(char S[]) { int i = 0; // Stores the frequencies // of each character int freq[26] = { 0 }; // Traverse over the string while (S[i] != '\0') { // Increment the count of // each character by 1 freq[S[i] - 'a']++; // Increment the index i++; } // Function call to print // the frequencies printFrequency(freq); } // Driver Code int main() { char S[100] = "geeksforgeeks"; findFrequncy(S); } Output:e - 4 f - 1 g - 2 k - 2 o - 1 r - 1 s - 2Complexity of the above method Time Complexity: O(N) Auxiliary Space: O(26) Comment More infoAdvertise with us Next Article C program to find the frequency of characters in a string A arifshaikh Follow Improve Article Tags : Strings Hash C Programs DSA frequency-counting +1 More Practice Tags : HashStrings Similar Reads C Program to Find the Length of a String The length of a string is the number of characters in it without including the null character (â\0â). In this article, we will learn how to find the length of a string in C.The easiest way to find the string length is by using strlen() function from the C strings library. Let's take a look at an exa 2 min read C Program to Print the Length of a String using Pointers C language provides a built-in function strlen() but in this article, we will learn how to find and print the length of the string using pointers in C.The easiest method to find the length of a string using pointers is by calculating difference between the pointers to the first and last character of 2 min read Find the Length of Character Array in C In C, a character array is a collection of elements of the âcharâ data type that are placed in contiguous memory locations and are often used to store strings. The length of a character array is defined as the total number of characters present in the array, excluding the null character ('\0') at th 2 min read Length of a String Without Using strlen() Function in C The length of a string is the number of characters in it without including the null character. C language provides the strlen() function to find the lenght of the string but in this article, we will learn how to find length of a string without using the strlen() function.The most straightforward met 2 min read How to Find Length of a String Without string.h and Loop in C? C language provides the library for common string operations including string length. Otherwise, a loop can be used to count string length. But is there other ways to find the string length in C apart from above two methods. In this article, we will learn how to find length of a string without strin 2 min read Like