struct matrix_nfo {
 int **matrix;
 int size;
 int ssize;
};

// Read and return data in an array with size and search square size (first two values of the matrix file)
int **readmatrix(char *file, struct matrix_nfo *mnfo) {

 int size = 0;                                  // Size of the matrix; declared from the file later
 int ssize = 0;                                 // Size of the search square; declared from the file later

 FILE *fd = fopen(file,"r");                    // File descriptor to our matrix input.

 int strlen = 1;                                // Keeping track of the temporary string storage size.
 char *str = malloc(sizeof(char)*strlen);       // Temporary string storage

 // Tracking ourselves while reading the matrix from the file.
 int rows = 0;
 int cols = 0;

 // Variables for tokenizing the data.
 char *token;                                   // Next delimited string token
 char *toksave;                                 // Where strtok_r stores some info
 char *tokstr;                                  // Some other pointer that strtok_r makes use of

 // Where we'll be storing our character input
 char in;

 int x = 0;                                     // Random counter variable

 while(!feof(fd)) {
  in = fgetc(fd);
  if(in != '\n') {
   str[strlen-1] = in;
   str = realloc(str,++strlen);
  } else {
   // printf("%s\n",str);
   for(tokstr=str; ; tokstr=NULL) {
    token = strtok_r(tokstr, "/", &toksave);
    if(token == NULL)
     break;
    if(rows == 0 && cols == 0) {
     size = atoi(token);
     (*mnfo).size = size;
     (*mnfo).matrix = malloc(sizeof(int *)*size);
     for(x=0; x<size; x++)
      (*mnfo).matrix[x] = malloc(0);
    } else if(rows == 0 && cols == 1) {
     ssize = atoi(token);
     (*mnfo).ssize = ssize;
    } else {
     (*mnfo).matrix[rows-1] = realloc((*mnfo).matrix[rows-1],sizeof(int)*cols);
     (*mnfo).matrix[rows-1][cols-1] = atoi(token);
    }
    cols++;
   }
   memset(str,0,strlen);
   strlen = 1;
   rows++;
   cols=1;
  }
 }
 return 0;
}

// Search through the matrix for the largest sum of numbers in given square in the matrix
int matrix(int **matrix, int size, int ssize) {

 int posh,posw; // position (in the matrix) variable declaration
 posh = 0;
 posw = 0;

 int offh,offw; // offset (start of matrix) variable declaration
 offh = 0;
 offw = 0;

 int totalsum = 0;
 int totalsumtmp = 0;
 int oldposh = 0;
 int oldposw = 0;
 int lsh = 0;
 int lsw = 0;

 for(offh=0;offh<=size;offh++) {
  for(offw=0;offw<=size;offw++) {
   for(posh=offh;posh<=size-(size-ssize)+offh;posh++) {
    if((size-(size-ssize)+offh) > size)
    continue;
    for(posw=offw;posw<=size-(size-ssize)+offw;posw++) {
     if((size-(size-ssize)+offw) > size)
      continue;
     oldposh = posh;
     oldposw = posw;
     // printf("matrix[%d][%d] => %dx%d = %3.d\n",posh,posw,posh+1,posw+1,matrix[posh][posw]);
     totalsumtmp += matrix[posh][posw];
    }
    posw = 0; // reset the column position
   }
   // check largest here
   if(totalsum < totalsumtmp) {
    totalsum = totalsumtmp;
    lsh = oldposh;
    lsw = oldposw;
    // printf("new total is %d [%d:%d] \n",totalsum,lsh,lsw);
   }
   totalsumtmp = 0;
  }
 }
 // printf("oldposh %d oldposw %d lsh %d lsw %d\n",oldposh,oldposw,lsh,lsw);
 for(posh=lsh-ssize;posh<=(size-(size-ssize))+lsh-1;posh++) {
  for(posw=lsw-ssize;posw<=(size-(size-ssize))+lsh-1;posw++) {
   printf("matrix[%d][%d] => %dx%d = %5.d\n",posh,posw,posh+1,posw+1,matrix[posh][posw]);
  }
  posw = 0; // reset the column position
 }
 printf("Largest square of %dx%d dimensions has a sum of %d.\n",ssize+1,ssize+1,totalsum);
 return 0;
}