Max

#include <stdio.h>
#include <math.h>
int main(void) {
  const char * fname = "test.dat";
  char line[BUFSIZ];
  double amp, time, max, max_abs = 0;
  FILE *in = fopen(fname, "r");
  while (fgets(line, BUFSIZ, in)) {
    sscanf(line, "%lf%lf", &time, &amp);
    if (fabs(amp) > max_abs) {
      max = amp;
      max_abs = fabs(max);
    }
  }
  fclose(in);
  printf("max: %.7lf\n", max);
  return 0;
}