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

int mystrlen(const char * str)
{
    int len;

    for (len = 0; str[len] != '\0'; len++);

    return len;
}

int main() {
    int i = 0, j, k, max = 0, flag = 0, z=0, start=0;
    int len;
    char *word = nullptr, *max_word = nullptr, *temp = nullptr;
    puts("Input text with the $ in the end:");
    max_word = (char*)malloc(sizeof(char) * 1);
    temp = (char*)malloc(sizeof(char) * 1);
    word = (char*)malloc(sizeof(char) * 1);
    for (i = 0; (word[i] = getchar()) != '\n'; i++);
    word[i] = '\0';
    len = mystrlen(word);
    for (i = 0; i < len+1; i++) {
        //if (start == 0) {
        //  for(int j = i; word[j] != ' ' && word[j] != ',' && word[j] != '\n' && word[j] != '.' && word[j] != '!' && word[j] != '?' && word[j] != ';' && word[j] != ':' && word[j] != '\0'; j++){
        //  }
        //  j--;
        //  max_word = (char*)realloc(max_word, sizeof(char) * j);
        //  max_word[j] = '\0';
        //  for (int t = 0; t < j; t++) {
        //      max_word[t] = word[t];
        //  }
        //}
        if (word[i] != ' ' && word[i] != ',' && word[i] != '\n' && word[i] != '.' && word[i] != '!' && word[i] != '?' && word[i] != ';' && word[i] != ':' && word[j] != '\0') {
            continue;
        }
        else {
            z = i - z;
            if (word[i + 1] == ' ') i++;
            temp = (char*)realloc(temp, sizeof(char) * z);
            temp[z] = '\0';
            int m = start;
            for (int t = 0; t < z; t++) {
                temp[t] = word[m];
                m++;
            }
            for (k = 0; k < z; k++) {
                for (j = k; j < z; j++) {
                    if (temp[j] == temp[k] && j != k)
                        flag = 1;
                }
                    if (k == z - 1 && flag == 0 && k > max) {
                        max = k;
                        int lent = mystrlen(temp);
                        max_word = (char*)realloc(max_word, sizeof(char) * lent);
                        temp[lent] = '\0';
                        max_word = temp;
                    }
                }
            z = i + 1;
            start = i + 1;
            flag = 0;
            }
        }
    printf("%s\n", max_word);
    return 0;
}