text: //  Copyright 2013 Google Inc. All Rights Reserved.
  //
  //  Licensed under the Apache License, Version 2.0 (the "License");
  //  you may not use this file except in compliance with the License.
  //  You may obtain a copy of the License at
  //
  //      http://www.apache.org/licenses/LICENSE-2.0
  //
  //  Unless required by applicable law or agreed to in writing, software
  //  distributed under the License is distributed on an "AS IS" BASIS,
  //  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  //  See the License for the specific language governing permissions and
  //  limitations under the License.
  
  #include <stdio.h>
  #include <string.h>
  #include <math.h>
  
  #include <stdlib.h> // mac os x
  // #include <malloc.h>
  
  const long long max_size = 2000;         // max length of strings
  const long long N = 40;                  // number of closest words that will be shown
  const long long max_w = 50;              // max length of vocabulary entries
  
  int main(int argc, char **argv) {
    FILE *f;
    char st1[max_size];
    char *bestw[N];
    char file_name[max_size], st[100][max_size];
    float dist, len, bestd[N], vec[max_size];
    long long words, size, a, b, c, d, cn, bi[100];
    char ch;
    float *M;
    char *vocab;
    if (argc < 2) {
      printf("Usage: ./distance <FILE>\nwhere FILE contains word projections in the BINARY FORMAT\n");
      return 0;
    }
    strcpy(file_name, argv[1]);
    f = fopen(file_name, "rb");
    if (f == NULL) {
      printf("Input file not found\n");
      return -1;
    }
    fscanf(f, "%lld", &words);
    fscanf(f, "%lld", &size);
    vocab = (char *)malloc((long long)words * max_w * sizeof(char));
    for (a = 0; a < N; a++) bestw[a] = (char *)malloc(max_size * sizeof(char));
    M = (float *)malloc((long long)words * (long long)size * sizeof(float));
    if (M == NULL) {
      printf("Cannot allocate memory: %lld MB    %lld  %lld\n", (long long)words * size * sizeof(float) / 1048576, words, size);
      return -1;
    }
    for (b = 0; b < words; b++) {
      a = 0;
      while (1) {
        vocab[b * max_w + a] = fgetc(f);
        if (feof(f) || (vocab[b * max_w + a] == ' ')) break;
        if ((a < max_w) && (vocab[b * max_w + a] != '\n')) a++;
      }
      vocab[b * max_w + a] = 0;
      for (a = 0; a < size; a++) fread(&M[a + b * size], sizeof(float), 1, f);
      len = 0;
      for (a = 0; a < size; a++) len += M[a + b * size] * M[a + b * size];
      len = sqrt(len);
      for (a = 0; a < size; a++) M[a + b * size] /= len;
    }
    fclose(f);
    while (1) {
      for (a = 0; a < N; a++) bestd[a] = 0;
      for (a = 0; a < N; a++) bestw[a][0] = 0;
      a = 0;
      st1[0] = 0;
      gets(st1);
      if (!strcmp(st1, "")) break;
      cn = 0;
      b = 0;
      c = 0;
      while (1) {
        st[cn][b] = st1[c];
        b++;
        c++;
        st[cn][b] = 0;
        if (st1[c] == 0) break;
        if (st1[c] == ' ') {
          cn++;
          b = 0;
          c++;
        }
      }
      cn++;
      for (a = 0; a < cn; a++) {
        for (b = 0; b < words; b++) if (!strcmp(&vocab[b * max_w], st[a])) break;
        if (b == words) b = -1;
        bi[a] = b;
        printf("%s\n", st[a]);
        if (b == -1) {
          printf("Out of dictionary word!\n");
          break;
        }
      }
      if (b == -1) continue;
      for (a = 0; a < size; a++) vec[a] = 0;
      for (b = 0; b < cn; b++) {
        if (bi[b] == -1) continue;
        for (a = 0; a < size; a++) vec[a] += M[a + bi[b] * size];
      }
      len = 0;
      for (a = 0; a < size; a++) len += vec[a] * vec[a];
      len = sqrt(len);
      for (a = 0; a < size; a++) vec[a] /= len;
      for (a = 0; a < N; a++) bestd[a] = -1;
      for (a = 0; a < N; a++) bestw[a][0] = 0;
      for (c = 0; c < words; c++) {
        a = 0;
        for (b = 0; b < cn; b++) if (bi[b] == c) a = 1;
        if (a == 1) continue;
        dist = 0;
        for (a = 0; a < size; a++) dist += vec[a] * M[a + c * size];
        for (a = 0; a < N; a++) {
          if (dist > bestd[a]) {
            for (d = N - 1; d > a; d--) {
              bestd[d] = bestd[d - 1];
              strcpy(bestw[d], bestw[d - 1]);
            }
            bestd[a] = dist;
            strcpy(bestw[a], &vocab[c * max_w]);
            break;
          }
        }
      }
      for (a = 0; a < N; a++) printf(" %s\t%f\n", bestw[a], bestd[a]);
    }
    return 0;
  }
  