Exercise 1-19. Write a function reverse(s)

02-vars-and-math.c

@@ -4,6 +4,8 @@
 #define  UPPER  300
 #define  STEP   20
 
+float convert(int f);
+
 /* print Fahrenheit-Celsius table */
 int main()
 {
@@ -11,5 +13,10 @@ int main()
 
 	printf("Fahrenheit\tCelsius\n=======================\n");
 	for (fahr = UPPER; fahr >= LOWER; fahr = fahr - STEP)
-		printf("%3d\t\t%7.1f\n", fahr, (5.0/9.0)*(fahr-32));
+		printf("%3d\t\t%7.1f\n", fahr, convert(fahr));
+}
+
+float convert(int fahr)
+{
+	return (5.0/9.0)*(fahr-32);
 }

10-one-word-per-line.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main()
+{
+	int c;
+
+	while((c = getchar()) != EOF) {
+		if (c == ' ' || c == '\n' || c == '\t')
+			printf("\n");
+		else
+			printf("%c", c);
+	}
+
+}

11-arrays.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+
+/* count digits, white space, others */
+int main()
+{
+	int c, i, nwhite, nother;
+	int ndigit[10];
+
+	nwhite = nother = 0;
+	for(i = 0; i < 10; ++i)
+		ndigit[i] = 0;
+
+	while ((c = getchar()) != EOF)
+		if (c >= '0' && c <= '9')
+			++ndigit[c-'0'];
+		else if (c == ' ' || c == '\n' || c == '\t')
+			++nwhite;
+		else
+			++nother;
+
+	printf("digits =");
+	for (i = 0; i < 10; ++i)
+		printf(" %d", ndigit[i]);
+	printf(", white space = %d, other = %d\n",
+		nwhite, nother);
+}

12-histogram.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+
+#define IN       1
+#define OUT      0
+#define MAXERROR "WARNING: Word length '%d' exceeded 99\n"
+
+int main()
+{
+	int c, i, j, state, count, top;
+	int wordl[100];
+
+	count = state = top = OUT;
+	for(i = 0; i < 100; ++i)
+		wordl[i] = 0;
+
+	while ((c = getchar()) != EOF) {
+		if (c == ' ' || c == '\n' || c == '\t') {
+			state = OUT;
+			if (count > 0 && count < 100)
+				++wordl[count];
+			else if (count >= 100)
+				printf(MAXERROR, count);
+			count = 0;
+		} else {
+			++count;
+			if (state == OUT)
+				state = IN;
+		}
+	}
+
+	if (count > 0 && count < 100)
+		++wordl[count];
+	else if (count >= 100)
+		printf(MAXERROR, count);
+
+	for (i = 0; i < 100; ++i)
+		if (wordl[i] > top)
+			top = wordl[i];
+
+	printf("\n");
+	for (i = 0; i < 100; ++i)
+		if (wordl[i] > 0)
+			printf("%2d ", i);
+
+	printf("\n");
+	for (i = 1; i <= top; ++i) {
+		for (j = 0; j < 100; ++j) {
+			if (wordl[j] >= i)
+				printf(" # ");
+			else if (wordl[j] > 0)
+				printf("   ");
+		}
+		printf("\n");
+	}
+}

13-functions.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+
+int power(int m, int n);
+
+/* test power function */
+int main()
+{
+	int i;
+
+	for (i = 0; i < 10; ++i)
+		printf("%d %d %d\n", i, power(2,i), power(-3,i));
+	return 0;
+}
+
+/* power: raise base to n-th power; n >= 0 */
+int power(int base, int n)
+{
+	int i, p;
+
+	p = 1;
+	for (i = 1; i <= n; ++i)
+		p = p * base;
+	return p;
+}

14-char-arrays.c

@@ -0,0 +1,81 @@
+#include <stdio.h>
+#define MAXLINE 1000 /* maximum input line size */
+#define MINLINE 0
+
+int getline(char line[], int maxline);
+void copy(char to[], char from[]);
+void trim(char line[], int len);
+void reverse(char to[], char from[], int len);
+
+/* print longest input line */
+main()
+{
+	int len;
+	int max;
+	int c;
+	char line[MAXLINE];
+	char enil[MAXLINE];
+
+	max = 0;
+	while((len = getline(line, MAXLINE)) > 0) {
+		if (line[len-1] != '\n') {
+			while ((c=getchar())!=EOF && c!='\n')
+				++len;
+			if (c == '\n')
+				++len;
+		}
+		if (len >= MINLINE) {
+			reverse(enil, line, len);
+			printf("%s", enil);
+		}
+	}
+	return 0;
+}
+
+/* getline: read a line into s, return length */
+int getline(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;
+}
+
+/* copy: copy 'from' into 'to': assume to is big enough */
+void copy(char to[], char from[])
+{
+	int i;
+
+	i = 0;
+	while ((to[i] = from[i]) != '\0')
+		++i;
+}
+
+/* trim: remove extraneous blanks and tabs */
+void trim(char s[], int len)
+{
+	int i;
+
+	for (i = len-2; i >= 0; --i)
+		if (s[i] == ' ' || s[i] == '\t')
+			s[i] = '\0';
+		else
+			return;
+}
+
+void reverse(char to[], char from[], int len)
+{
+	int i;
+
+	i = 0;
+	while ((to[i] = from[len-1]) != '\0') {
+		++i;
+		--len;
+	}
+}

Makefile

@@ -4,7 +4,7 @@ OBJS = $(patsubst %.c,bin/%,$(wildcard *.c))
 all: $(OBJS)
 
 $(OBJS):
-	$(CC) -o ./$@ $(patsubst bin/%,%.c,$@)
+	$(CC) -o ./$@ $(patsubst bin/%,%.c,$@) -ansi
 
 clean:
 	$(RM) ./bin/*