#define FMT "INSERT INTO data (v1, v2, v3, v4) VALUES ('%s', '%s', '%s', '%s')"
#define NSTMTS 3
#define BUFSIZE 1024

int i;
char stmts[NSTMTS][BUFSIZE];

for (i = 0; i < NSTMTS; i++) {
  /* ... get data into the array f ... */
  assert(snprintf(stmts[i], BUFSIZE, FMT, f[0], f[1], f[2], f[3]) < BUFSIZE - 1);
}