hist.c

该文件包括几篇比较关于LDPC编码核心的基础读物

#include<stdio.h>
#include<math.h>

/************************************************
Histogram - Takes floating point numbers from 
stdin and delivers a histogram of integers to 
stdout. 

This program is Copyright (C) 2003 by
Andrew W. Eckford, and is released into the
public domain so long as this entire comment
is preserved in the source.
************************************************/

/************************************************
To compile:

cc -lm -o hist hist.c

To use:

hist FIRST_BIN INC NUM_BINS

where FIRST_BIN is the center of the first bin,
INC is the difference between bin centers, and
NUM_BINS is the number of bins.  The program's
output consists of NUM_BINS integers.

Example:

cat data.txt | hist 0 1 5

produces a histogram of the floating point
numbers in data.txt with five bins, with bin
centers at 0, 1, 2, 3, and 4.
************************************************/



int main(int argc, char *argv[])  {

	float start,inc,data_in;
	int index,bins;
	int c;
	long int *data;

	sscanf(argv[1], "%f", &start);
	sscanf(argv[2], "%f", &inc);
	sscanf(argv[3], "%d", &bins);

	data = (long int *)calloc(bins,sizeof(long int));

	for (c = 0; c < bins; c++) { data[c] = 0; }

	while( fscanf(stdin,"%f",&data_in) != EOF ) {

		index = (int)rintf((data_in - start)/inc);

		if (index < 0) { index = 0; }
		if (index >= bins) { index = bins - 1; }

		data[index]++;

	}

	for (c = 0; c < bins; c++) { fprintf(stdout,"%ld ",data[c]); }

	free(data);

}