How to sort data in .txt file

I have a .txt file with floating point values on each line:
3.14 5.221 0.55 4.77
6.12 2.13 9.33 1.2
0.99 4.22 3.56 8.95 3.125
9.0575 4.897542 120.2324 55.555

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 256
int main(int argc, char *argv[])
{
    if(argc !=2)
    {
        printf("Invalid format.\n");
        return -1;
    }
    FILE *fin = fopen(argv[1], "rt");
    if(!fin)
    {
        printf("ERROR opening the file.\n");
        return 1;
    }
    char buf[MAX];
    int i = 0;
    float v[MAX], n;
    while(fgets(buf, MAX, fin))
    {
        buf[strlen(buf)-1] = '\0';
        char *word = strtok(buf, " ");
        while(word != NULL)
        {
            printf("Word : %s <-> %.3f\n", word, atof(word));
            //v[i] = atof(word);
            //i++;
            n = atof(word);
            word = strtok(NULL, " ");
            printf("%f\n", n);
        }
    }
    fclose(fin);
    return 0;
}

---

I wanna print the sets sorted by the number of digits in the decimal part. I'm thinking of using qsort maybe, but I tried placing each value in an array and only garbage values were printed. Why is that?

Quote:

---

Originally Posted by ipsilante

I wanna print the sets sorted by the number of digits in the decimal part.

---

You might want to elaborate on this. For example, by "set" you presumably mean a set of values on a line. Do you want to sort the values within each set? Do you want to sort the sets themselves with respect to each other?

Quote:

---

Originally Posted by ipsilante

I'm thinking of using qsort maybe, but I tried placing each value in an array and only garbage values were printed. Why is that?

---

You probably can use qsort, but you're sorting an array of strings, not floats. If you try sorting floats, it simply won't work: how many "digits in the decimal part" is there?

Desired output would be:
6.12 2.13 9.33 1.2 // 7 digits in total in the decimal part
3.14 5.221 0.55 4.77 // 9 digits in total in the decimal part
0.99 4.22 3.56 8.95 3.125 // 11 digits in total in the decimal part
9.0575 4.897542 120.2324 55.555 // 17 digits in total in the decimal part

Well that was nothing like I expected.

Code:

---

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

int main ( ) {
  const char *seps = " \n";
  FILE *in = fopen("foo.txt","r");
  char buff[BUFSIZ];
  while ( fgets(buff,BUFSIZ,in) ) {
    char *p;
    for ( p = strtok(buff,seps) ; p ; p = strtok(NULL,seps) ) {
      char *q = strchr(p,'.');
      printf("Len after . in %s is %zd\n", p, strlen(q+1));
    }
  }
  fclose(in);
}

$ ./a.out
Len after . in 3.14 is 2
Len after . in 5.221 is 3
Len after . in 0.55 is 2
Len after . in 4.77 is 2
Len after . in 6.12 is 2
Len after . in 2.13 is 2
Len after . in 9.33 is 2
Len after . in 1.2 is 1
Len after . in 0.99 is 2
Len after . in 4.22 is 2
Len after . in 3.56 is 2
Len after . in 8.95 is 2
Len after . in 3.125 is 3
Len after . in 9.0575 is 4
Len after . in 4.897542 is 6
Len after . in 120.2324 is 4
Len after . in 55.555 is 3

---