串行直方圖程序

串行直方圖程序

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>

#define MAXLINE 10000001

int main()
{
    double *ptd;
    char *ptc;
    FILE *fp;
    int i = 0;   
    struct timeval t_read;
    double readCost=0,countCost=0;
    struct timeval t_start,t_end;
    double readS, start, finish;
    int count[10]={0};
    int num=0;

    ptd = (double *)malloc(MAXLINE * sizeof(double));
    ptc = (char *)malloc(10 * sizeof(char));

    gettimeofday(&t_read,NULL);
    readS = t_read.tv_sec*1000 + t_read.tv_usec/1000.0;

    if((fp = fopen("data.txt","r")) == NULL)
    {
      printf("Can't open \n");
      exit(1);
    }
    i=0;
    while(fgets(ptc, 10, fp) != NULL && ptc[0] != '\n' && i < MAXLINE)
    {       
        ptd[i] = atof(ptc);
        i++;
    }
    num = i;
    free(ptc);
    if(fclose(fp)!=0)
    {
        fprintf(stderr,"Error closing file\n");
    }
    gettimeofday(&t_start,NULL);
    start = t_start.tv_sec*1000 + t_start.tv_usec/1000.0;
 
    for(i=0; i<num; i++)
    {
        count[(int)ptd[i]]++;
    }

    gettimeofday(&t_end,NULL);
    finish = t_end.tv_sec*1000 + t_end.tv_usec/1000.0;

    readCost = start - readS;
    countCost = finish - start;
    printf("\nread file spend: %f ms\n\ncount datas spend: %f ms\n\n",readCost,countCost);

    for(i=0;i<10;i++)
    {
        printf("%d<=x<%d: %d條\n",i,i+1,count[i]);
    }
    free(ptd);
    return 0;
}