gistfile1.c

/***********************************************************************
 * This programs plots histograms. 
 * Input is fed through the console/command-line/terminal.
 * To compile issue : 
 * gcc -o hist <name_you_saved>.c
 * Ignore warnings... (Remove them if you can. :) )
 * Run as ./hist with options. 
 * 
 * Options :
 * 1. -c<space><character> specifies the character which will be used to 
 * draw bars.
 * 2. -m specifies to print the mean.
 * 3. -v specifies to print the value on top of the bar. 
 * 
 * Sample Input :
 * ./hist -v -c $ -m 2 3 10 5 7
 * 
 * Output :
 * $$         2
 * $$$        3
 * $$$$$$$$$$ 10
 * $$$$$      5
 * $$$$$$$    7
 * The mean is : 5.400000
 * 
 * It is easy to add more options. Look in the code. !
 * 
 * License : Do what the fuck you want to with this code... 
 * 
 * ********************************************************************/

#include <stdio.h>
#include <stdlib.h>

/* The structure below holds program options */
typedef struct
{
	unsigned int start ; /* Determines from where the data starts. */
	char unit_bar ; /* Character to draw. */
	char verbose ; /* Whether to print value. */
	char mean ;  /* Whether to display mean. */
} print_options ;

/* Checks whether the string is a valid unsigned int */
char isuint(const char* string)
{
	unsigned int i ; 
	for(i=0; string[i]!='\0'; ++i)
		if(string[i] < 48 || string[i] > 57)
			return 0 ;
	return 1 ;
}

void print_usage_message()
{
	puts("Usage : hist-plot [OPTIONS] ...data list... \n\n Options : \n\t-c character to draw\n\t-v to display value on top of bars\n\t-m to display mean\n");
}

void print_error_message()
{
	puts("Something went wrong...");
}

unsigned int find_max(const unsigned int *data, unsigned int size)
{
	unsigned int i = 1u, max = data[0]; 
	for(; i<size; ++i)
		if(max < data[i])
			max = data[i] ; 
	return max ;
}

float mean(const unsigned int *data, unsigned int size)
{
	unsigned int i ; 
	float sum = 0.0f ;
	for(i=0; i<size; ++i)
		sum += (float)data[i] ;
	return sum/(float)size ;
}

/* Prints the histogram */
char printh(const unsigned int *data, unsigned int size, print_options ops)
{
	unsigned int i, j, max ; 
	char **matrix = malloc(sizeof(char*)*size); 
	if(!matrix)
		return 0 ; 
	max = find_max(data, size); 
	for(i=0; i<size; ++i)
	{
		matrix[i] = malloc(sizeof(char)*(max+1)); 
		if(!matrix[i])
			return 0 ; 
		for(j=0; j<max; ++j)
			matrix[i][j] = ((j < data[i]) ? ops.unit_bar : ' ') ;
		matrix[i][max] = '\0' ; /* Make a valid string. */
	}
		 
	for(i=0; i<size; ++i)
		(ops.verbose) ? printf("%s %u\n", matrix[i], data[i]) : 
			printf("%s\n", matrix[i]);
			
	if(ops.mean)
		printf("The mean is : %f\n", mean(data, size)); 

	return 1 ; 
}

char parse_options(const char** argv, print_options* options)
{
	unsigned int i = 1 ; 
	int ret = 1 ; 
	while((argv[i][0] == '-') && (argv[i] != NULL)) 
	{
		switch(argv[i][1])
		{
			/* If -c option, then read the character to draw */
			case 'c' : 
				++i ; 
				(*options).unit_bar = argv[i][0] ; 
				break ;
				
			case 'v' : 
				(*options).verbose = 1 ; 
				break ;
			
			case 'm' :
				(*options).mean = 1 ;
				break ; 
			
			default :
				return 0 ;
		}
		++i ;	
	}
	(*options).start = i ; 
	return ret ; 
}

char parse_data(int argc, const char** argv, print_options ops) 
{
	unsigned int* data, i, j ;
	data = malloc(sizeof(unsigned int)*(argc-ops.start)); 
	if(!data)
		return 0 ;
	for(i=ops.start, j=0; i<argc; ++i)
	{
		if(isuint(argv[i]))
		{
			data[j] = atoi(argv[i]); 
			++j ;
		}
		else
			return 0 ; 
	}
	return printh(data, j, ops);
}			

int main(int argc, char **argv) {
	
	/* Default options : All turned off, draws '=' character. */
	print_options ops = { .start = 1, .unit_bar = '=', .verbose = 0, .mean = 0 } ; 
	
	if(argc < 2 || !parse_options(argv, &ops))
	{
		print_usage_message() ; 
		return 0 ;
	}
	
	if(!parse_data(argc, argv, ops))
		print_error_message() ; 
		
	return 0;
}