C studies

character_occurence_histogram.c

#include <stdio.h>
#include <string.h>

#define MAX_HISTOGRAM_SYMBOLS 40

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

	unsigned int n_symbols[26];
	memset(n_symbols, 0, sizeof(int)*26);

	unsigned int total_chars;

	while((ch = getchar()) != '\n')
	{
		if(ch >= 'A' && ch <= 'Z')
		{
			n_symbols[ch - 'A']++;
		}
		else if(ch >= 'a' && ch <= 'z')
		{
			n_symbols[ (ch^0b100000) - 'A']++;
		}

		total_chars++;
	}

	char i;
	int j;
	float perc;
	int hist_symbols;
	for(i=0;i<26;i++)
	{
		if(n_symbols[i] !=0)
		{
			putchar('A' + i);
			perc = (float)n_symbols[i]/total_chars;
			hist_symbols = perc * MAX_HISTOGRAM_SYMBOLS;

			for(j = 0; j < MAX_HISTOGRAM_SYMBOLS; j++)
			{
				if(j<hist_symbols)
				{
					putchar('#');
				}
				else
				{
					putchar(' ');
				}
			}

			printf("|\t%.1f\n", perc*100.0);
		}
	}

	return 0;
}

Digit_counter.c

#include <stdio.h>
#include <string.h>

int main(int argc, char const *argv[])
{
	
	int ndigits[10] = {0};
	memset(ndigits, 0, 10 * sizeof(int));//init with zeroes
	int n_spaces = 0;
	int n_others = 0;

	int ch;
	while((ch = getchar()) != '\n')
	{
		if(ch >= '0' && ch <= '9')
		{
			ndigits[ch - '0']++;
		}
		else if(ch == ' ')
		{
			n_spaces++;
		}
		else
		{
			n_others++;
		}
	}

	int i;
	for(i = 0; i<10; i++)
	{
		printf("%d: %d\n", i, ndigits[i]);
	}

	printf("%s: %d\n%s: %d\n", "Spaces: ", n_spaces, "Others: ", n_others);


	return 0;
}

fahrengheit_to_celsius.c

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

#define STEP 20

int main(int argc, char const *argv[])
{
	if(argc < 4)
	{
		printf("You didn't provide all the necessary parameters\n");
		return 1;
	}

	int start = atoi(argv[1]);
	int end = atoi(argv[2]);

	float celsius = 0;

	printf("%s\t%s\n", "Fahrengheit", "Celsius");
	for(int i = start; i <= end; i=i+STEP)
	{
		celsius = 5.0 * (i-32.0) / 9.0;
		printf("%10d\t%6.1f\n", i, celsius);
	}

	return 0;
}

helloworld.c

#include <stdio.h>

int main(int argc, char const *argv[])
{
	printf("Hallo, ");
	printf("%s", "Welt!");
	printf("\n");
	printf("%d%s\n", argc, " arguments");

	return 0;
}

input_chars_counter.c

#include <stdio.h>

int main(int argc, char const *argv[])
{
	//counts symbols
	unsigned int newlines, tabs, spaces;
	newlines = tabs = spaces = 0;
	int ch;
	while(ch != 'a'){

		ch = getchar();
		if(ch == '\n')
		{
			newlines++;
		}
		else if (ch == ' ')
		{
			spaces++;
		}
		else if (ch == '\t')
		{
			tabs++;
		}
	}
	printf("%s: %d\n%s: %d\n%s: %d\n", "Newlines", newlines, "Tabs", tabs, "Spaces", spaces);
	return 0;
}

input_echo.c

#include <stdio.h>

int main(int argc, char const *argv[])
{
	printf("%d\n", EOF);

	int ch;
	// Assignment can be written together with expressions in condition check.
	while( (ch = getchar()) != EOF)
	{
		putchar(ch);
		// ch ^= 0b100000;
		// putchar(ch);

	}

	return 0;
}

input_line_counter.c

#include <stdio.h>

int main(int argc, char const *argv[])
{
	//counts symbols
	double n;
	int ch;
	while(ch != 'a'){

		ch = getchar();
		if(ch == '\n')
		{
			n++;
		}
	}
	printf("%.0f\n", n);
	return 0;
}

input_symbol_counter.c

#include <stdio.h>

int main(int argc, char const *argv[])
{
	//counts symbols
	double nc;
	for(nc = 0; getchar() != 'a'; ++nc)
		;
	printf("%.0f\n", nc);
	return 0;
}

redundant_space_deleter.c

#include <stdio.h>

int main(int argc, char const *argv[])
{
	int ch = 0;
	int prev_ch = 0;

	while((ch = getchar()) != 'a')
	{
		if(prev_ch == ' ' && ch == ' ')
			;
		else{
			putchar(ch);
		}

		prev_ch = ch;
	}

	return 0;
}

symbol_replacer.c

#include <stdio.h>

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

	while((ch = getchar()) != 'a')
	{
		if(ch == '\b' || ch == '\t')
		{
			putchar('\\');
		}
		else
		{
			putchar(ch);
		}

	}

	return 0;
}

wc_simplified.c

#include <stdio.h>

#define OUT 0
#define IN 1

int main(int argc, char const *argv[])
{
	unsigned long bytes, words, lines;
	bytes = words = lines = 0;
	int in_word = OUT;

	int ch;
	while( (ch = getchar()) != 'A' )
	{
		bytes++;
		if(ch == '\n')
		{
			lines++;
		}
		if(ch == ' ' || ch == '\n')
		{
			if(in_word == IN)
			{
				words++;
			}
			in_word = OUT;
		}
		else
		{
			in_word = IN;
		}

	}

	printf("%s: %lu\n%s: %lu\n%s: %lu\n", "Lines", lines, "Words", words, "Bytes", bytes );

	return 0;
}

word_length_histogram.c

#include <stdio.h>
#include <string.h>

#define IN 1
#define OUT 0

#define MAX_LENGTH 200

#define MAX_HISTOGRAM_SYMBOLS 40

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

	int in_word = OUT; //flag that shows if the caret is in word now

	int lengths[MAX_LENGTH];
	memset(lengths, 0, sizeof(int) * MAX_LENGTH);


	int wordlen = 0;
	int total_words = 0; //amount of words
	while((ch = getchar()) != '\n')
	{
		if(ch == ' ' || ch == ',' || ch == '.')
		{
			if(in_word == IN)
			{
				in_word = OUT;
				lengths[wordlen]++;
				total_words++;
				wordlen = 0;
			}
		}
		else
		{
			in_word = IN;
			wordlen++;
		}
	}
	//last word
	if(in_word == IN)
	{
		in_word = OUT;
		lengths[wordlen]++;
		total_words++;
		wordlen = 0;
	}

	printf("Total %d\n",total_words);

	//calculate percentages and draw histograms
	int i, j;
	float perc;
	int hist_symbols_amount = 0;
	for(i = 1; i < MAX_LENGTH; i++)	{
		if(lengths[i] != 0){
			perc = ((float)lengths[i])/total_words;
			hist_symbols_amount = perc * MAX_HISTOGRAM_SYMBOLS;
			printf("%3d: ", i);

			for(j = 0; j < MAX_HISTOGRAM_SYMBOLS; j++)
			{
				if(j < hist_symbols_amount){
					printf("#");
				}
				else{
					printf(" ");
				}
			}
			printf("|\t%.1f\n",perc*100);
		}
	}


	return 0;
}