Q4

using namespace std;
 
int* getCharCountArray(char* str)
{
    int* count = (int*)calloc(sizeof(int), NO_OF_CHARS);
    int i;
    for (i = 0; *(str + i); i++)
        count[*(str + i)]++;
    return count;
}
 
int firstNonRepeating(char* str)
{
    int* count = getCharCountArray(str);
    int index = -1, i;
 
    for (i = 0; *(str + i); i++) {
        if (count[*(str + i)] == 1) {
            index = i;
            break;
        }
    }

    free(count);
    return index;
}
 
int main()
{
    char str[] = "geeksforgeeks";
    int index = firstNonRepeating(str);
    if (index == -1)
        cout << "Either all characters are repeating or "
            "string is empty";
    else
        cout << "First non-repeating character is "<<
            str[index];
    getchar();
    return 0;
}