3.6

Author: Heatwave

chapter-3-control-flow/1.binsearch.c chapter-3-control-flow/01.binsearch.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <string.h>
+#include <limits.h>
+
+void itoa(int n, char s[]);
+void reverse(char[]);
+
+
+main()
+{
+	int a = 0;
+	char s[10];
+	itoa(a, s);
+	printf("%s\n", s);
+
+	a = INT_MIN;
+	itoa(a, s);
+	printf("%s\n", s);
+
+	a = INT_MAX;
+	itoa(a, s);
+	printf("%s\n", s);
+}
+
+void itoa(int n, char s[])
+{
+	int i, sign;
+	int preN = n;
+	int nIsMinNagetive = n != 0 && n == -n;
+
+	if ((sign = n) < 0) {
+		if (nIsMinNagetive) {
+			n += 1;
+			n = -n;
+		} else {
+			n = -n;
+		}
+	}
+
+	i = 0;
+	do {
+		s[i++] = n % 10 + '0';
+	} while ((n /= 10) > 0);
+
+	if (sign < 0)
+		s[i++] = '-';
+
+	s[i] = '\0';
+	reverse(s);
+
+	if (nIsMinNagetive)
+		s[strlen(s) - 1] += 1;
+}
+
+void reverse(char s[])
+{
+	int c, i, j;
+
+	for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
+		c = s[i];
+		s[i] = s[j];
+		s[j] = c;
+	}
+}

chapter-3-control-flow/2.switch.c chapter-3-control-flow/02.switch.c

@@ -0,0 +1,69 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+#define MAX_LEN 1024
+
+void itob(int n, char s[], int b);
+void itob2(int n, char s[], int b);
+void reverse(char[]);
+
+main()
+{
+	int n = 255;
+	char s[MAX_LEN];
+	itob(n, s, 16);
+	printf("n: %d, s: %s\n", n, s);
+
+	n = INT_MAX;
+	itob(n, s, 16);
+	printf("n: %d, s: %s\n", n, s);
+
+	n = 2048;
+	itob(n, s, 2);
+	printf("n: %d, s: %s\n", n, s);
+
+	n = 2048;
+	itob(n, s, 8);
+	printf("n: %d, s: %s\n", n, s);
+
+	n = INT_MIN;
+	itob(n, s, 16);
+	printf("n: %d, s: %s\n", n, s);
+}
+
+void itob(int n, char s[], int b)
+{
+	int i;
+	int sign = n;
+
+	i = 0;
+	do {
+		char c;
+		int m = abs(n % b);
+		if (m < 10)
+			c = m + '0';
+		else 
+			c = m - 10 + 'a';
+		s[i++] = c;
+	} while (n /= b);
+
+	if (sign < 0)
+		s[i++] = '-';
+
+	s[i] = '\0';
+	reverse(s);
+}
+
+void reverse(char s[])
+{
+	int c, i, j;
+
+	for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
+		c = s[i];
+		s[i] = s[j];
+		s[j] = c;
+	}
+}
+

chapter-3-control-flow/3.escape.c chapter-3-control-flow/03.escape.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+#define MAX_LEN 1024
+
+void itoa(int n, char s[], int minWidth);
+void reverse(char[]);
+
+
+main()
+{
+	int a = 0;
+	char s[MAX_LEN];
+	itoa(a, s, 5);
+	printf("a: %d, %s\n", a, s);
+
+	a = INT_MIN;
+	itoa(a, s, 20);
+	printf("INT_MIN: %d, %s\n", a, s);
+
+	a = INT_MAX;
+	itoa(a, s, 15);
+	printf("INT_MAX: %d, %s\n", a, s);
+
+	a = 1234567890;
+	itoa(a, s, 5);
+	printf("a: %d, %s\n", a, s);
+}
+
+void itoa(int n, char s[], int minWidth)
+{
+	int i;
+	int sign = n;
+
+	i = 0;
+	do {
+		s[i++] = abs(n % 10) + '0';
+	} while (n /= 10);
+
+	if (sign < 0)
+		s[i++] = '-';
+
+	int needSpace = minWidth - strlen(s);
+	while (needSpace-- > 0) {
+		s[i++] = ' ';
+	}
+
+	s[i] = '\0';
+	reverse(s);
+}
+
+void reverse(char s[])
+{
+	int c, i, j;
+
+	for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
+		c = s[i];
+		s[i] = s[j];
+		s[j] = c;
+	}
+}
+