Q:

Empty Character Constant in C

I've tried changing it to double quotes, but this is wrong, also tried figuring out what it means, but the compiler keeps giving me the same error
[Error] empty character constant

#include <stdio.h>

main()
{
    int c, i, nwhite, nother;
    int ndigit[10];
    nwhite = nother = 0;
    for(i = 0; i < 10; i++)
    ndigit[i] = 0;      

    while (( c = getchar()) != EOF)
    if( c >= '0' && c <= '9')
    ++ndigit[c - '0'];
    else if (c == '' || c == '\n' || c == '\n')
    ++nwhite;
    else 
    ++nother;

    printf("digits = ");
    for(i = 0; i < 10; i++)
        printf ("%d", ndigit[i]);
        printf(", white space = %d, other = %d \n", nwhite, nother);        
}

A:

The empty character constant error is because of the following comparison in the else if clause.
c == '' //  '' is empty

Replace '' with ' '.

