Indexing

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <iostream>
#include <algorithm>

using namespace std;

struct index
{
    char str[90];
    int ar2[1000];
    int max;
};
struct index ar[5000];

int compare(const void *a, const void *b)
{
    char str2[100], str3[100];
    strcpy(str2, ((index *)a)->str);
    strcpy(str3, ((index *)b)->str);

    if (strcmp(str2, str3) > 0) return 1;
    return -1;
}

int main()
{
    int t = 1, i = 0, j, k, l, a, b, c, d, x, y, z, n, no = 0;
    char ch, str2[100], str3[100];
    for (i = 0; i < 5000; i++) ar[i].max = 0;

    //freopen("sample.txt", "r", stdin);
    gets(str2);
    i = 0, ch = str2[0];
    while(gets(str2))
    {
        l = 0;
        for (j = 0; ;j++)
        {
            if (isalpha(str2[j]))
            {
                no = 1;
                str3[l++] = str2[j];
            }
            else if (no == 1)
            {
                no = 0, str3[l] = 0;
                if (str3[0] != ch)
                {
                    l = 0;
                    continue;
                }

                d = 0;
                for (k = 0; k < i; k++)
                {
                    if (strcmp(str3, ar[k].str) == 0)
                    {
                        d = 1;
                        if (ar[k].max == 0) ar[k].ar2[ar[k].max++] = t;
                        else if (ar[k].ar2[ar[k].max - 1] != t) ar[k].ar2[ar[k].max++] = t;
                        break;
                    }
                }
                if (d == 0)
                {
                    strcpy(ar[i].str, str3);
                    ar[i++].ar2[ar[k].max++] = t;
                }
                l = 0;
            }
            if (str2[j] == 0) break;
        }
        t++;
    }
    qsort(ar, i, sizeof(index), compare);

    for (j = 0; j < i; j++)
    {
        printf("%s", ar[j].str);
        for (k = 0; k < ar[j].max; k++) printf(" %d", ar[j].ar2[k]);
        putchar(10);
    }
    return 0;
}