C Programming: Find the Frequency of Characters

Last update on August 06 2025 13:02:33 (UTC/GMT +8 hours)

18. Frequency of a Character

Write a program in C to find the frequency of characters.

Sample Solution:

C Code:

#include <stdio.h>

int main() {
    char str[1000], choice; // Declare a character array to store the string and a variable for the character to find frequency
    int i, ctr = 0; // Declare variables for iteration and counting frequency

    printf("\n\nFind the Frequency of Characters :\n"); // Display information about the task
    printf("--------------------------------------\n");

    printf("Input the string : ");
    fgets(str, sizeof str, stdin); // Read a string from the standard input (keyboard)

    printf("Input the character to find frequency: ");
    scanf("%c", &choice); // Read the character for which frequency needs to be found

    for (i = 0; str[i] != '\0'; ++i) {
        if (choice == str[i]) { // Check if the character matches the current character in the string
            ++ctr; // Increment the counter if the character matches
        }
    }
    printf("The frequency of '%c' is : %d\n\n", choice, ctr); // Display the frequency of the chosen character
	
	return 0; // Return 0 to indicate successful execution of the program
}

Output:

Find the Frequency of Characters :                                                                                            
--------------------------------------                                                                                        
Input the string : This is a test string                                                                                      
Input the character to find frequency: i                                                                                      
The frequency of 'i' is : 3

Flowchart:

Flowchart: Find the Frequency of Characters

For more Practice: Solve these Related Problems:

Write a C program to count the number of times a given character appears in a string using pointer arithmetic.
Write a C program to compute the frequency of a specific character without using any library functions.
Write a C program to determine the percentage occurrence of a character in a string.
Write a C program to count a character's frequency recursively and output the result.

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