From 552bc70b77d4fca54929b46190128721b93d887c Mon Sep 17 00:00:00 2001
From: Adam Carpenter <gitlab@53hor.net>
Date: Tue, 23 Jul 2019 12:09:24 -0400
Subject: Cleaned up directory.

---
 ch2/2-02.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 ch2/2-03.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 ch2/2-04.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 ch2/2-05.c | 20 ++++++++++++++++++++
 ch2/2-06.c | 22 ++++++++++++++++++++++
 ch2/2-07.c | 19 +++++++++++++++++++
 ch2/2-08.c | 21 +++++++++++++++++++++
 ch2/2-09.c | 40 ++++++++++++++++++++++++++++++++++++++++
 ch2/2-10.c |  0
 ch2/2-2.c  | 46 ----------------------------------------------
 ch2/2-3.c  | 42 ------------------------------------------
 ch2/2-4.c  | 43 -------------------------------------------
 ch2/2-5.c  | 20 --------------------
 ch2/2-6.c  | 22 ----------------------
 ch2/2-7.c  | 19 -------------------
 ch2/2-8.c  | 21 ---------------------
 ch2/2-9.c  | 40 ----------------------------------------
 17 files changed, 253 insertions(+), 253 deletions(-)
 create mode 100644 ch2/2-02.c
 create mode 100644 ch2/2-03.c
 create mode 100644 ch2/2-04.c
 create mode 100644 ch2/2-05.c
 create mode 100644 ch2/2-06.c
 create mode 100644 ch2/2-07.c
 create mode 100644 ch2/2-08.c
 create mode 100644 ch2/2-09.c
 create mode 100644 ch2/2-10.c
 delete mode 100644 ch2/2-2.c
 delete mode 100644 ch2/2-3.c
 delete mode 100644 ch2/2-4.c
 delete mode 100644 ch2/2-5.c
 delete mode 100644 ch2/2-6.c
 delete mode 100644 ch2/2-7.c
 delete mode 100644 ch2/2-8.c
 delete mode 100644 ch2/2-9.c

(limited to 'ch2')

diff --git a/ch2/2-02.c b/ch2/2-02.c
new file mode 100644
index 0000000..52b0a2e
--- /dev/null
+++ b/ch2/2-02.c
@@ -0,0 +1,46 @@
+#include<stdio.h>
+
+
+#define MAX_LEN 10
+
+
+/*
+ * Reads STDIN into string s. Is allowed to use && and ||.
+ */
+void getline_with_ops(char s[]) {
+    char c;
+    int i;
+    int lim = MAX_LEN;
+
+    for (i = 0; i < lim - 1 && (c = getchar()) != '\n' && c != EOF; ++i) 
+        s[i] = c;
+
+    s[i] = '\0';
+}
+
+
+/*
+ * Reads STDIN into string s. Is not allowed to use && or ||.
+ */
+void getline_without_ops(char s[]) {
+    char c;
+    int i;
+    int lim = MAX_LEN;
+
+    for (i = 0; i < lim - 1; ++i)
+        if ((c = getchar()) != '\n')
+            if (c != EOF)
+                s[i] = c;
+
+    s[i] = '\0';
+}
+
+
+int main() {
+    char s[MAX_LEN];
+
+    //getline_with_ops(s);
+    getline_without_ops(s);
+
+    printf("%s\n", s);
+}
diff --git a/ch2/2-03.c b/ch2/2-03.c
new file mode 100644
index 0000000..54ce89f
--- /dev/null
+++ b/ch2/2-03.c
@@ -0,0 +1,42 @@
+#include <stdio.h>
+
+
+unsigned int htoi(char hex[]) {
+    char c;
+    int i;
+    int length;
+    int power;
+    unsigned int result;
+
+    for (length = 0; hex[length] != '\0'; ++length)
+
+    power = 1;
+    result = 0;
+
+    for (i = length - 1; i >= 0; --i) {
+        c = hex[i];
+        printf("%c\n", c);
+
+        if (c >= 'a' && c <= 'f')
+            c = c - 'a' + 10;
+        else if (c >= 'A' && c <= 'F')
+            c = c - 'A' + 10;
+        else if (c >= '0' && c <= '9')
+            c = c - '0';
+        else if (c == 'x' || c == 'X')
+            break;
+        else
+            return 0;
+
+        result += c * power;
+        power *= 16;
+    }
+
+    return result;
+}
+
+
+int main() {
+    char hex[] = "0x589";
+    printf("%d\n", htoi(hex));
+}
diff --git a/ch2/2-04.c b/ch2/2-04.c
new file mode 100644
index 0000000..3f122bb
--- /dev/null
+++ b/ch2/2-04.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+
+
+void squeeze_char(char s[], char c) {
+    int i;
+    int j;
+
+    for (i = j = 0; s[i] != '\0'; i++)
+        if (s[i] != c)
+            s[j++] = s[i];
+
+    s[j] = '\0';
+}
+
+
+void squeeze_str(char s1[], char s2[]) {
+    int i;
+
+    for (i = 0; s2[i] != '\0'; ++i)
+        squeeze_char(s1, s2[i]);
+}
+
+
+void squeeze_all(char s1[], char s2[]) {
+    int i;
+    int j;
+    int k;
+
+    for (k = 0; s2[k] != '\0'; ++k) {
+        for (i = j = 0; s1[i] != '\0'; ++i)
+            if (s1[i] != s2[k])
+                s1[j++] = s1[i];
+
+        s1[j] = '\0';
+    }
+}
+
+
+int main() {
+    char squeezed[] = "abracadabra";
+    squeeze_all(squeezed,"abc");
+    printf("%s\n", squeezed);
+}
diff --git a/ch2/2-05.c b/ch2/2-05.c
new file mode 100644
index 0000000..495473c
--- /dev/null
+++ b/ch2/2-05.c
@@ -0,0 +1,20 @@
+#include<stdio.h>
+
+int any(char s1[], char s2[]) {
+    int i;
+    int j;
+
+    for (i = 0; s2[i] != '\0'; ++i)
+        for (j = 0; s1[j] != '\0'; ++j)
+            if (s2[i] == s1[j])
+                return j;
+
+    return -1;
+}
+
+int main() {
+    char test_str[] = "blargh";
+    char test_chars[] = "cab";
+    int result = any(test_str, test_chars);
+    printf("%d\n", result);
+}
diff --git a/ch2/2-06.c b/ch2/2-06.c
new file mode 100644
index 0000000..918f583
--- /dev/null
+++ b/ch2/2-06.c
@@ -0,0 +1,22 @@
+#include<stdio.h>
+
+/*
+ * Set n bits in x starting at position p to rightmost n bits of y.
+ */
+
+unsigned setbits(unsigned x, unsigned p, unsigned n, unsigned y) {
+    // Create a basa from x that zeroes out all of the bits to be set.
+    unsigned a = x & ~(~(~0 << n) << (p + 1 - n));
+
+    // Create a mask from y that zeroes out all of the bits except those to set.
+    unsigned b = (y & ~(~0 << n)) << (p + 1 - n);
+
+    // Apply the mask to the base.
+    return a | b;
+}
+
+int main() {
+    printf("%x\n", setbits(0xaa, 3, 3, 0x33));
+    printf("%x\n", setbits(0x00, 3, 3, 0xff));
+    return 0;
+}
diff --git a/ch2/2-07.c b/ch2/2-07.c
new file mode 100644
index 0000000..bf9fed1
--- /dev/null
+++ b/ch2/2-07.c
@@ -0,0 +1,19 @@
+#include<stdio.h>
+
+/*
+ * Returns x with the n bits that begin at position p inverted (i.e., 1 changed
+ * into 0 and vice versa), leaving the others unchanged.
+ */
+
+unsigned invert(unsigned x, unsigned p, unsigned n) {
+    // Create mask where bits should be flipped.
+    unsigned mask = ~(~0 << n) << (p + 1 - n);
+
+    // Flip bits with mask.
+    return x ^ mask;
+}
+
+int main() {
+    printf("%x\n", invert(0xaa, 3, 3));
+    printf("%x\n", invert(0xff, 3, 3));
+}
diff --git a/ch2/2-08.c b/ch2/2-08.c
new file mode 100644
index 0000000..9f7adbd
--- /dev/null
+++ b/ch2/2-08.c
@@ -0,0 +1,21 @@
+#include<stdio.h>
+
+/*
+ * Returns the value of the integer x rotated to the right by n bit positions.
+ */
+
+unsigned rightrot(unsigned x, int n) {
+    unsigned mask = ~(~0 >> 1);
+
+    while (n-- > 0)
+        if (x & 1)
+            x = (x >> 1) | mask;
+        else
+            x >>= 1;
+
+    return x;
+}
+
+int main() {
+    printf("%x\n", rightrot(0xaa, 3));
+}
diff --git a/ch2/2-09.c b/ch2/2-09.c
new file mode 100644
index 0000000..5ab3241
--- /dev/null
+++ b/ch2/2-09.c
@@ -0,0 +1,40 @@
+#include <stdio.h>
+
+int bitcount_original(unsigned x);
+int bitcount(unsigned x);
+
+int main() {
+    printf("%d\n", bitcount_original(0xaa));
+    printf("%d\n", bitcount(0xaa));
+    return 0;
+}
+
+/*
+ * A binary subtraction operation will toggle the least-significant bits
+ * required for the subtraction. The `&` operation between two opposing bits
+ * will always result in 0. This is why using `x &= (x - 1)` will always delete
+ * the rightmost 1-bit in x; the least-significant 1-bit and all 1-bits
+ * generated from the subtraction operation will be zeroed out.
+ *
+ * This observation makes this implementation more efficient than
+ * `bitcount_original` simply because it requires fewer operations.
+ */
+int bitcount(unsigned x) {
+    int b;
+    
+    for (b = 0; x > 0; b++)
+        x &= (x - 1);
+
+    return b;
+}
+
+int bitcount_original(unsigned x) {
+    int b;
+
+    for (b = 0; x != 0; x >>= 1)
+        if (x & 01)
+            b++;
+
+    return b;
+}
+
diff --git a/ch2/2-10.c b/ch2/2-10.c
new file mode 100644
index 0000000..e69de29
diff --git a/ch2/2-2.c b/ch2/2-2.c
deleted file mode 100644
index 52b0a2e..0000000
--- a/ch2/2-2.c
+++ /dev/null
@@ -1,46 +0,0 @@
-#include<stdio.h>
-
-
-#define MAX_LEN 10
-
-
-/*
- * Reads STDIN into string s. Is allowed to use && and ||.
- */
-void getline_with_ops(char s[]) {
-    char c;
-    int i;
-    int lim = MAX_LEN;
-
-    for (i = 0; i < lim - 1 && (c = getchar()) != '\n' && c != EOF; ++i) 
-        s[i] = c;
-
-    s[i] = '\0';
-}
-
-
-/*
- * Reads STDIN into string s. Is not allowed to use && or ||.
- */
-void getline_without_ops(char s[]) {
-    char c;
-    int i;
-    int lim = MAX_LEN;
-
-    for (i = 0; i < lim - 1; ++i)
-        if ((c = getchar()) != '\n')
-            if (c != EOF)
-                s[i] = c;
-
-    s[i] = '\0';
-}
-
-
-int main() {
-    char s[MAX_LEN];
-
-    //getline_with_ops(s);
-    getline_without_ops(s);
-
-    printf("%s\n", s);
-}
diff --git a/ch2/2-3.c b/ch2/2-3.c
deleted file mode 100644
index 54ce89f..0000000
--- a/ch2/2-3.c
+++ /dev/null
@@ -1,42 +0,0 @@
-#include <stdio.h>
-
-
-unsigned int htoi(char hex[]) {
-    char c;
-    int i;
-    int length;
-    int power;
-    unsigned int result;
-
-    for (length = 0; hex[length] != '\0'; ++length)
-
-    power = 1;
-    result = 0;
-
-    for (i = length - 1; i >= 0; --i) {
-        c = hex[i];
-        printf("%c\n", c);
-
-        if (c >= 'a' && c <= 'f')
-            c = c - 'a' + 10;
-        else if (c >= 'A' && c <= 'F')
-            c = c - 'A' + 10;
-        else if (c >= '0' && c <= '9')
-            c = c - '0';
-        else if (c == 'x' || c == 'X')
-            break;
-        else
-            return 0;
-
-        result += c * power;
-        power *= 16;
-    }
-
-    return result;
-}
-
-
-int main() {
-    char hex[] = "0x589";
-    printf("%d\n", htoi(hex));
-}
diff --git a/ch2/2-4.c b/ch2/2-4.c
deleted file mode 100644
index 3f122bb..0000000
--- a/ch2/2-4.c
+++ /dev/null
@@ -1,43 +0,0 @@
-#include <stdio.h>
-
-
-void squeeze_char(char s[], char c) {
-    int i;
-    int j;
-
-    for (i = j = 0; s[i] != '\0'; i++)
-        if (s[i] != c)
-            s[j++] = s[i];
-
-    s[j] = '\0';
-}
-
-
-void squeeze_str(char s1[], char s2[]) {
-    int i;
-
-    for (i = 0; s2[i] != '\0'; ++i)
-        squeeze_char(s1, s2[i]);
-}
-
-
-void squeeze_all(char s1[], char s2[]) {
-    int i;
-    int j;
-    int k;
-
-    for (k = 0; s2[k] != '\0'; ++k) {
-        for (i = j = 0; s1[i] != '\0'; ++i)
-            if (s1[i] != s2[k])
-                s1[j++] = s1[i];
-
-        s1[j] = '\0';
-    }
-}
-
-
-int main() {
-    char squeezed[] = "abracadabra";
-    squeeze_all(squeezed,"abc");
-    printf("%s\n", squeezed);
-}
diff --git a/ch2/2-5.c b/ch2/2-5.c
deleted file mode 100644
index 495473c..0000000
--- a/ch2/2-5.c
+++ /dev/null
@@ -1,20 +0,0 @@
-#include<stdio.h>
-
-int any(char s1[], char s2[]) {
-    int i;
-    int j;
-
-    for (i = 0; s2[i] != '\0'; ++i)
-        for (j = 0; s1[j] != '\0'; ++j)
-            if (s2[i] == s1[j])
-                return j;
-
-    return -1;
-}
-
-int main() {
-    char test_str[] = "blargh";
-    char test_chars[] = "cab";
-    int result = any(test_str, test_chars);
-    printf("%d\n", result);
-}
diff --git a/ch2/2-6.c b/ch2/2-6.c
deleted file mode 100644
index 918f583..0000000
--- a/ch2/2-6.c
+++ /dev/null
@@ -1,22 +0,0 @@
-#include<stdio.h>
-
-/*
- * Set n bits in x starting at position p to rightmost n bits of y.
- */
-
-unsigned setbits(unsigned x, unsigned p, unsigned n, unsigned y) {
-    // Create a basa from x that zeroes out all of the bits to be set.
-    unsigned a = x & ~(~(~0 << n) << (p + 1 - n));
-
-    // Create a mask from y that zeroes out all of the bits except those to set.
-    unsigned b = (y & ~(~0 << n)) << (p + 1 - n);
-
-    // Apply the mask to the base.
-    return a | b;
-}
-
-int main() {
-    printf("%x\n", setbits(0xaa, 3, 3, 0x33));
-    printf("%x\n", setbits(0x00, 3, 3, 0xff));
-    return 0;
-}
diff --git a/ch2/2-7.c b/ch2/2-7.c
deleted file mode 100644
index bf9fed1..0000000
--- a/ch2/2-7.c
+++ /dev/null
@@ -1,19 +0,0 @@
-#include<stdio.h>
-
-/*
- * Returns x with the n bits that begin at position p inverted (i.e., 1 changed
- * into 0 and vice versa), leaving the others unchanged.
- */
-
-unsigned invert(unsigned x, unsigned p, unsigned n) {
-    // Create mask where bits should be flipped.
-    unsigned mask = ~(~0 << n) << (p + 1 - n);
-
-    // Flip bits with mask.
-    return x ^ mask;
-}
-
-int main() {
-    printf("%x\n", invert(0xaa, 3, 3));
-    printf("%x\n", invert(0xff, 3, 3));
-}
diff --git a/ch2/2-8.c b/ch2/2-8.c
deleted file mode 100644
index 9f7adbd..0000000
--- a/ch2/2-8.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include<stdio.h>
-
-/*
- * Returns the value of the integer x rotated to the right by n bit positions.
- */
-
-unsigned rightrot(unsigned x, int n) {
-    unsigned mask = ~(~0 >> 1);
-
-    while (n-- > 0)
-        if (x & 1)
-            x = (x >> 1) | mask;
-        else
-            x >>= 1;
-
-    return x;
-}
-
-int main() {
-    printf("%x\n", rightrot(0xaa, 3));
-}
diff --git a/ch2/2-9.c b/ch2/2-9.c
deleted file mode 100644
index 5ab3241..0000000
--- a/ch2/2-9.c
+++ /dev/null
@@ -1,40 +0,0 @@
-#include <stdio.h>
-
-int bitcount_original(unsigned x);
-int bitcount(unsigned x);
-
-int main() {
-    printf("%d\n", bitcount_original(0xaa));
-    printf("%d\n", bitcount(0xaa));
-    return 0;
-}
-
-/*
- * A binary subtraction operation will toggle the least-significant bits
- * required for the subtraction. The `&` operation between two opposing bits
- * will always result in 0. This is why using `x &= (x - 1)` will always delete
- * the rightmost 1-bit in x; the least-significant 1-bit and all 1-bits
- * generated from the subtraction operation will be zeroed out.
- *
- * This observation makes this implementation more efficient than
- * `bitcount_original` simply because it requires fewer operations.
- */
-int bitcount(unsigned x) {
-    int b;
-    
-    for (b = 0; x > 0; b++)
-        x &= (x - 1);
-
-    return b;
-}
-
-int bitcount_original(unsigned x) {
-    int b;
-
-    for (b = 0; x != 0; x >>= 1)
-        if (x & 01)
-            b++;
-
-    return b;
-}
-
-- 
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