find the file systems that are available in linux (vfs and mountable)

filesys.c

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


FILE *fp;
char buffer[1000];
struct fstypes {
    int vfs;
    char *filesystem;
} fs_types[30];
int maxfs = 0;

int k = 0;
int main(void)
{
    fp = fopen("/proc/filesystems", "r");
    if (!fp)
        return -1;

    while (fgets(buffer, sizeof(buffer), fp)) {
        int i = 0, j = 0;
        char var[90], val[90];

        memset(var, 0, sizeof(var));
        memset(val, 0, sizeof(val));

        while (buffer[i] != '\0') {
            if (buffer[i] == ' ' || buffer[i] == '\t')
                break;
            var[i] = buffer[i];
            i++;
        }

        var[i] = '\0';

        while (buffer[i] == ' ' || buffer[i] == '\t')
            i++;

        do {
            val[j] = buffer[i];
            j++; i++;
        } while (buffer[i] != '\n' &&
                 buffer[i] != '\0');

        val[j] = '\0';

        if (k < sizeof(fs_types) / sizeof(fs_types[0])) {
            fs_types[k].vfs = !!strlen(var);
            fs_types[k].filesystem = strdup(val);
            k++;
            maxfs++;
        }

    }

    return 0;
}