5.10

Author: Heatwave

chapter-5-pointers-and-arrays/28.echo-v1.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+main(int argc, char *argv[])
+{
+	int i;
+
+	for (i = 1; i < argc; i++)
+		printf("%s%s", argv[i], (i < argc-1) ? " " : "");
+	printf("\n");
+
+	return 0;
+}
+

chapter-5-pointers-and-arrays/29.echo-v2.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+main(int argc, char *argv[])
+{
+	while (--argc > 0)
+		printf("%s%s", *++argv, (argc > 1) ? " " : "");
+		//printf((argc > 1) ? "%s " : "%s", *++argv);
+	printf("\n");
+
+	return 0;
+}
+

chapter-5-pointers-and-arrays/30.find.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <string.h>
+#define MAXLINE 1000
+
+int mygetline(char *line, int max);
+
+main(int argc, char *argv[])
+{
+	char line[MAXLINE];
+	int found = 0;
+
+	if (argc != 2)
+		printf("Usage: find pattern\n");
+	else
+		while (mygetline(line, MAXLINE) > 0)
+			if (strstr(line, argv[1]) != NULL) {
+				printf("%s", line);
+				found++;
+			}
+	return found;
+}
+

chapter-5-pointers-and-arrays/31.find.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <string.h>
+
+#define MAXLINE 1000
+
+int mygetline(char *line, int max);
+
+main(int argc, char *argv[])
+{
+	char line[MAXLINE];
+	long lineno = 0;
+	int c, except = 0, number = 0, found = 0;
+
+	while (--argc > 0 && (*++argv)[0] == '-')
+		while (c = *++argv[0])
+			switch(c) {
+			case 'x':
+				except = 1;
+				break;
+			case 'n':
+				number = 1;
+				break;
+			default:
+				printf("find: illegal option %c\n", c);
+				argc = 0;
+				found = -1;
+				break;
+			}
+	if (argc != 1)
+		printf("Usage: find -x -n pattern\n");
+	else
+		while (mygetline(line, MAXLINE) > 0) {
+			lineno++;
+			if ((strstr(line, *argv) != NULL) != except) {
+				if (number)
+					printf("%ld:", lineno);
+				printf("%s", line);
+				found++;
+			}
+		}
+	return found;
+}
+

chapter-5-pointers-and-arrays/32.expr.c

@@ -0,0 +1,109 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAXOP 100
+#define NUMBER '0'
+
+int getop(char [], int, char **);
+void push(double);
+double pop(void);
+
+main(int argc, char **argv)
+{
+	int type;
+	double op2;
+	char s[MAXOP];
+
+	if (argc == 1) {
+		printf("Usage: expr 1 1 +\n");
+		return 1;
+	}
+
+	while ((type = getop(s, --argc, ++argv)) != EOF) {
+		switch (type) {
+		case NUMBER:
+			push(atof(s));
+			break;
+		case '+':
+			push(pop() + pop());
+			break;
+		case '*':
+			push(pop() * pop());
+			break;
+		case '-':
+			op2 = pop();
+			push(pop() - op2);
+			break;
+		case '/':
+			op2 = pop();
+			if (op2 != 0.0)
+				push(pop() / op2);
+			else
+				printf("error: zero divisor\n");
+			break;
+		default:
+			printf("error: unknown command %s\n", s);
+			break;
+		}
+	}
+
+	printf("Result: %g\n", pop());
+
+	return 0;
+}
+
+
+#define MAXVAL 100
+
+int sp = 0;
+double val[MAXVAL];
+
+void push(double f)
+{
+	if (sp < MAXVAL)
+		val[sp++] = f;
+	else
+		printf("error: stack full, can't push %g\n", f);
+}
+
+double pop(void)
+{
+	if (sp > 0)
+		return val[--sp];
+	else {
+		printf("error: stack empty\n");
+		return 0.0;
+	}
+}
+
+int getop(char *s, int argc, char **argv)
+{
+	if (argc == 0)
+		return EOF;
+
+	char *param = *argv;
+
+	int c;
+
+	while ((*s = c = *param++) == ' ' || c == '\t')
+		;
+
+	*++s = '\0';
+
+	if (!isdigit(c) && c != '.')
+		return c;
+
+	if (isdigit(c))
+		while (isdigit(*s++ = c = *param++))
+			;
+
+
+	if (c == '.')
+		while (isdigit(*s++ = c = *param++))
+			;
+
+	*s = '\0';
+
+	return NUMBER;
+}
+

chapter-5-pointers-and-arrays/33.detab.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+
+main(int argc, char *argv[])
+{
+	int c, n, i;
+	int cur;
+
+	if (argc == 1)
+		n = 8;
+	else if (argc == 2)
+		n = atoi(*++argv);
+	else {
+		printf("Usage: detab (8)(tab stop)\n");
+		return 1;
+	}
+
+	cur = 0;
+
+	while ((c = getchar()) != EOF) {
+		if (c == '\t') {
+			for (i = n - cur; i > 0; --i)
+				putchar(' ');
+
+			cur = 0;
+		} else {
+			putchar(c);
+			++cur;
+			if (cur >= n || c == '\n')
+				cur = 0;
+		}
+	}
+}
+

chapter-5-pointers-and-arrays/34.entab.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+
+#define MAXLINE 1000
+
+int myGetline(char line[], int maxline);
+
+main(int argc, char *argv[])
+{
+	int c, len;
+	int i;
+	char line[MAXLINE];
+	int tabstop;
+	int spaceCount;
+
+	if (argc == 1)
+		tabstop = 8;
+	else if (argc == 2)
+		tabstop = atoi(*++argv);
+	else {
+		printf("Usage entab (8)(tabstop)\n");
+		return 1;
+	}
+
+	while ((len = myGetline(line, MAXLINE)) > 0) {
+		spaceCount = 0;
+
+		for (i = 0; i < len; ++i) {
+			if (line[i] == ' ')
+				spaceCount++;
+			else
+				spaceCount = 0;
+
+			if (spaceCount == tabstop) {
+			}
+		}
+		printf("%s", line);
+	}
+}
+
+int myGetline(char s[], int lim)
+{
+	int c, i;
+
+	for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
+		s[i] = c;
+	if (c == '\n') {
+		s[i] = c;
+		++i;
+	}
+	s[i] = '\0';
+	return i;
+}

chapter-5-pointers-and-arrays/35.detab-arg.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+main(int argc, char *argv[])
+{
+}
+

chapter-5-pointers-and-arrays/36.entab-arg.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+main(int argc, char *argv[])
+{
+}
+

chapter-5-pointers-and-arrays/37.tail.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <string.h>
+
+#define MAXLINES 50000
+#define MAXLEN 10000
+
+int mygetline(char *line, int max);
+
+char *alloc(int);
+void afree(char*);
+
+main(int argc, char *argv[])
+{
+	int n;
+
+	if (argc == 1)
+		n = 10;
+	else if (argc == 2 && (*++argv)[0] == '-') {
+		n = atoi(*argv + 1);
+		if (n < 1)
+			n = 10;
+	} else {
+		printf("Usage: tail -n\n");
+		return 1;
+	}
+
+	char line[MAXLEN], *lineptr[MAXLINES];
+	int len;
+	char *p;
+	int lines = 0;
+
+	while ((len = mygetline(line, MAXLEN)) > 0) {
+		p = alloc(len + 1);
+		strcpy(p, line);
+		lineptr[lines++] = p;
+	}
+
+
+	int i = lines - n;
+	i = (i >= 0) ? i : 0;
+
+	while (n-- > 0 && i <= lines) {
+		printf("%s", lineptr[i++]);
+	}
+
+	return 0;
+}
+

chapter-5-pointers-and-arrays/mygetline.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+
+int mygetline(char s[], int lim)
+{
+	int c, i;
+	i = 0;
+	while (--lim > 0 && (c = getchar()) != EOF && c != '\n')
+		s[i++] = c;
+	if (c == '\n')
+		s[i++] = c;
+	s[i] = '\0';
+	return i;
+}