C program to Return Maximum occurring character in an input string

C – Strings : 

Strings are actually one-dimensional array of characters terminated by a null character ‘\0’. Thus a null-terminated string contains the characters that comprise the string followed by a null.

String is a sequence of characters. char data type is used to represent one single character in C. So if you want to use a string in your program then you can use an array of characters.

The declaration and definition of the string using an array of chars is similar to declaration and definition of an array of any other data type.

Any string ends with a terminating null character ‘\0’. An array definition in such a way should include null character ‘\0’ as the last element.

Here is source code of the C program to Return Maximum occurring character in an input string. The C program is successfully compiled and run(on Codeblocks) on a Windows system. The program output is also shown in below.

SOURCE CODE : :

/*  C program to Return Maximum occurring character in an input string  */

#include <stdio.h>
#define MAX_SIZE 100 //Maximum size of the string
#define MAX_CHARS 255 //Maximum characters allowed


int main()
{
    char string[MAX_SIZE];
    int frequency[MAX_CHARS]; //Stores frequency of each character
    int i = 0, max;
    int ascii;

    printf("\nEnter any string: ");
    gets(string);

    /* Initializes frequency of all characters to 0 */
    for(i=0; i<MAX_CHARS; i++)
    {
        frequency[i] = 0;
    }


    /* Finds frequency of each characters */
    i=0;
    while(string[i] != '\0')
    {
        ascii = (int)string[i];
        frequency[ascii] += 1;

        i++;
    }


    /* Finds maximum frequency */
    max = 0;
    for(i=0; i<MAX_CHARS; i++)
    {
        if(frequency[i] > frequency[max])
            max = i;
    }


    printf("\nHighest frequency of ['%c'] is [ %d ].\n", max, frequency[max]);

    return 0;
}

Output:

/*  C program to Return Maximum occurring character in an input string  */

Enter any string: CodezClub

Highest frequency of ['C'] is [ 2 ].

Process returned 0

Above is the source code for C program to Return Maximum occurring character in an input string which is successfully compiled and run on Windows System.The Output of the program is shown above .