Character array example

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);
 }

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 +1,49 @@
+#include <stdio.h>
+#define MAXLINE 1000 /* maximum input line size */
+
+int getline(char line[], int maxline);
+void copy(char to[], char from[]);
+
+/* print longest input line */
+main()
+{
+	int len;
+	int max;
+	char line[MAXLINE];
+	char longest[MAXLINE];
+
+	max = 0;
+	while((len = getline(line, MAXLINE)) > 0)
+		if (len > max) {
+			max = len;
+			copy(longest, line);
+		}
+	if (max > 0)
+		printf("%s", longest);
+	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;
+}

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/*