C Programming Code Examples

C > Strings Code Examples

program to find minimum occurring character in a string

program to find minimum occurring character in a string

Write a C program to find minimum occurring character in a string using loop. How to find lowest frequency character in a string using loop in C programming. Program to find minimum frequency character in a given string in C.

    Input string from user, store it in some variable say str.
    Declare another array to store frequency of all alphabets, say freq[26]. I have declared size of freq as 26 since there are 26 alphabets in English.
    Initialize frequencies of all alphabets in freq array to 0.
    Find frequency of each character present in the string.
    Minimum occurring character in string is minimum occurring value in the freq array.

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

int main()
{
    char str[maxsize];
    int freq[MAX_CHARS]; //Stores frequency of each character
    int j = 0, min;
    int ascii;

    printf("Enter any string: ");
    gets(str);

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

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

        j++;
    }

    /* Finds minimum frequency */
    min = 0;
    for(j=0; j<MAX_CHARS; j++)
    {
        if(freq[j] != 0)
        {
            if(freq[min] == 0 || freq[j] < freq[min])
                min = j;
        }
    }

    printf("Minimum occurring character is '%c' = %d.", min, freq[min]);

    return 0;
}