#include "stdio.h"

#define M 151

main()

{ void acor();

  float y[M];

  int i,j,m=M;

  float x[M];

  FILE *fp1,*fp2;

  fp1=fopen("SEIS.PRN","r");

  fp2=fopen("Seis_acor.xls","w");

  for(i=0;i

  {

fscanf(fp1,"%d %f",&j,&x[i]);

printf("%d %f\n",j,x[i]);

  }

  acor(x,m,y);

  for(i=-m+1;i<=-1;i++)

  fprintf(fp2,"] \t .4f\n",i,y[-i]);

  for(i=0;i<=m-1;i++)

  fprintf(fp2,"] \t .4f\n",i,y[i]);

  fclose(fp1);

  fclose(fp2);

}

void acor(x,m,y)

  float x[],y[];

  int m;

{ int i,j;

  for(i=0;i<=m-1;i++)

{ y[i]=0.0;

  for(j=0;j<=m-1;j++)

    if(j-i>=0&&j-i<=m-1)y[i]=y[i]+x[j]*x[j-i];

}

}

数据SEIS.PRN为一合成地震记录：