8 files changed, 205 insertions, 0 deletions
diff --git a/6.1/Makefile b/6.1/Makefile
new file mode 100644
index 0000000..eaee48d
--- /dev/null
+++ b/6.1/Makefile
@@ -0,0 +1,11 @@
+objects = main.o getch.o word.o key.o
+
+keys : $(objects)
+	cc -o keys $(objects)
+
+main.o : word.h key.h
+word.o : getch.h
+
+.PHONY : clean
+clean :
+	rm keys $(objects)
diff --git a/6.1/getch.c b/6.1/getch.c
new file mode 100644
index 0000000..2b86efe
--- /dev/null
+++ b/6.1/getch.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <error.h>
+#include <errno.h>
+#include "getch.h"
+
+#define MAXBUFF	100
+
+char buff[MAXBUFF];
+static size_t top;
+
+void ungetch(char c)
+{
+	if (top < MAXBUFF)
+		buff[top++] = c;
+	else
+		error(EXIT_FAILURE, ENOBUFS , "getch");
+}
+
+char getch(void)
+{
+	return (top > 0) ? buff[--top] : getchar();
+}
diff --git a/6.1/getch.h b/6.1/getch.h
new file mode 100644
index 0000000..cbfe8ad
--- /dev/null
+++ b/6.1/getch.h
@@ -0,0 +1,2 @@
+void ungetch(char c);
+char getch(void);
diff --git a/6.1/key.c b/6.1/key.c
new file mode 100644
index 0000000..33757ee
--- /dev/null
+++ b/6.1/key.c
@@ -0,0 +1,22 @@
+#include <string.h>
+#include "key.h"
+
+int bsearch(char *word, struct key tab[], int n)
+{
+	int cond;
+	int low, high, mid;
+
+	low = 0;
+	high = n - 1;
+	while (low <= high) {
+		mid = (low+high)/2;
+		if ((cond = strcmp(word, tab[mid].word)) < 0)
+			high = mid - 1;
+		else if (cond > 0)
+			low = mid + 1;
+		else 
+			return mid;
+	}
+
+	return -1;
+}
diff --git a/6.1/key.h b/6.1/key.h
new file mode 100644
index 0000000..1cba74e
--- /dev/null
+++ b/6.1/key.h
@@ -0,0 +1,13 @@
+#ifndef KEY_H
+
+#define NKEYS (sizeof(keytab) / sizeof(keytab[0]))
+
+struct key {
+	const char *word;
+	int count;
+};
+
+#define KEY_H
+#endif
+
+int bsearch(char *word, struct key tab[], int n);
diff --git a/6.1/main.c b/6.1/main.c
new file mode 100644
index 0000000..ce53539
--- /dev/null
+++ b/6.1/main.c
@@ -0,0 +1,70 @@
+#include <stdio.h>
+#include <ctype.h>
+#include "word.h"
+#include "key.h"
+
+#define MAXWORD 100
+
+struct key keytab[] = {
+	"#define", 0,
+	"#elif", 0,
+	"#else", 0,
+	"#endif", 0,
+	"#error", 0,
+	"#if", 0,
+	"#ifdef", 0,
+	"#ifndef", 0,
+	"#include", 0,
+	"#pragma", 0,
+	"#undef", 0,
+	"auto", 0,
+	"break", 0,
+	"case", 0,
+	"char", 0,
+	"const", 0,
+	"continue", 0,
+	"default", 0,
+	"do", 0,
+	"double", 0,
+	"else", 0,
+	"enum", 0,
+	"extern", 0,
+	"float", 0,
+	"for", 0,
+	"goto", 0,
+	"if", 0,
+	"int", 0,
+	"long", 0,
+	"register", 0,
+	"return", 0,
+	"short", 0,
+	"signed", 0,
+	"sizeof", 0,
+	"static", 0,
+	"struct", 0,
+	"switch", 0,
+	"typedef", 0,
+	"union", 0,
+	"unsigned", 0,
+	"void", 0,
+	"volatile", 0,
+	"while", 0,
+};
+
+int main(void)
+{
+	int n;
+	char word[MAXWORD];
+
+	while (getword(word, MAXWORD) != EOF)
+		if (isalpha(word[0]) || word[0] == '#')
+			if ((n = bsearch(word, keytab, NKEYS)) >= 0)
+				keytab[n].count++;
+
+	for (n = 0; n < NKEYS; ++n)
+		if(keytab[n].count > 0)
+			printf("%4d %s\n",
+				keytab[n].count, keytab[n].word);
+
+	return 0;
+}
diff --git a/6.1/word.c b/6.1/word.c
new file mode 100644
index 0000000..538198f
--- /dev/null
+++ b/6.1/word.c
@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <ctype.h>
+#include "getch.h"
+#include "word.h"
+
+char scomment();
+
+int getword(char *word, int lim)
+{
+	int instr = 0;
+	char *w = word;
+	
+	while (isblank(*w = getch()) || *w == '"' || *w == '/') {
+		if (*w == '"') {
+			while ((*w = getch()) != '"' && *w != EOF)
+				;
+			if (*w == EOF)
+				ungetch(*w);
+		} else if (*w == '/' && !scomment()) {
+			break;
+		}
+	}
+
+	if (isalpha(*w)) {
+		while ((isalnum(*w) || *w == '_') && --lim > 0)
+			*++w = getch();
+		ungetch(*w--);
+	} else if (*w == '#' && --lim > 0) {
+		do {
+			*++w = getch();
+		} while (isalpha(*w) && --lim > 0);
+		ungetch(*w--);
+	}
+
+	*++w = '\0';
+	return word[0];
+}
+
+char scomment()
+{
+	char c;
+
+	switch (c = getch()) {
+	case '/' :
+		while ((c = getch()) != EOF && c != '\n')
+			;
+		if (c == EOF)
+			ungetch(c);
+
+		return '/';
+	case '*' :
+		while ((c = getch()) != EOF && !(c == '*' && (c = getch()) == '/'))
+			if (c == '*')
+				ungetch(c);
+		if (c == EOF)
+			ungetch(c);
+
+		return '*';
+	default:
+		ungetch(c);
+		return 0;
+	}
+}
diff --git a/6.1/word.h b/6.1/word.h
new file mode 100644
index 0000000..5714c50
--- /dev/null
+++ b/6.1/word.h
@@ -0,0 +1 @@
+int getword(char *word, int len);