这个或许可以满足你的要求
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <string.h>

#define BUFSIZE 512

int main(int argc,char *argv[])
{
  FILE *ifp,*ofp;
  char buf[BUFSIZE];
  int number;       // record entry number
  int i;
  double *x,*y,*z;

  if((ifp = fopen("diala.xyz","r+")) == NULL)   // input file handle
  {
    printf("Cannot open this file!\n");
        exit(1);
  }
  if((ofp = fopen(argv[1],"w+")) == NULL)   // output filename obtained from first commandline parameter
  {
    printf("Cannot write to this file!\n");
        exit(1);
  }
  fgets(buf,BUFSIZE,ifp);   // read record entry number
  number = atoi(buf);

  // memory allocation for three arrays
  x = (double *)malloc(sizeof(double) * number);
  y = (double *)malloc(sizeof(double) * number);
  z = (double *)malloc(sizeof(double) * number);


  i = 0;
  while(fgets(buf,BUFSIZE,ifp) != NULL)  // read info line by line
  {
    sscanf(buf,"%*d%*s%lf%lf%lf",&x[i],&y[i],&z[i]);
        fprintf(ofp,"%lf  %lf  %lf\n",x[i],y[i],z[i]);  // write into output file
        i++;
  }

  fclose(ifp);
  fclose(ofp);

  // release memory
  free(x);
  free(y);
  free(z);
  

  return 0;

}

2楼: Originally posted by 绿遍山原 at 2013-06-26 15:17:39
只要坐标就只读每行前四列:
比如
fgetl(line, LINE_MAX, fp);
int n = sscanf(line, "%s %lg %lg %lg", name, &x, &y, &z);
if (n < 4) error("Invalid input"