C Program - Character's frequency

#include <stdio.h>
#include <conio.h>
#include <string.h>

int main()
{
    char string[100];
    int c = 0, count[26] = {0};

    printf("Enter a string\n");
    gets(string);

    while ( string[c] != '\0' )
    {
        /* Considering characters from 'a' to 'z' only */

        if ( string[c] >= 'a' && string[c] <= 'z' )
            count[string[c]-'a']++;

        c++;
    }

    for ( c = 0 ; c < 26 ; c++ )
    {
        if( count[c] != 0 )
            printf("%c occurs %d times in the entered string.\n",c+'a',count[c]);
    }

    getch();
    return 0;
}

Output

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