1 files changed, 52 insertions, 0 deletions
diff --git a/ch01/ex13-histogram.c b/ch01/ex13-histogram.c
new file mode 100644
index 0000000..14002a5
--- /dev/null
+++ b/ch01/ex13-histogram.c
@@ -0,0 +1,52 @@
+#include <stdio.h>
+
+#define IN  1    /* inside a word */
+#define OUT 0    /* outside a word */
+
+/* print a histogram of word lengths */
+int main()
+{
+	int c, i, j, nc, state;
+	int ndigit[10];
+
+	for (i = 0; i < 10; ++i)
+		ndigit[i] = 0;
+
+	nc = 0;
+	state = OUT;
+	while ((c = getchar()) != EOF) {
+		if (c == ' ' || c == '\n' || c == '\t') {
+			if (state == IN) {
+				i = nc - 1;
+				if (i > 9)
+					i = 9;
+				++ndigit[i];
+				nc = 0;
+			}
+			state = OUT;
+		} else if (state == OUT) {
+			state = IN;
+		}
+
+		if (state == IN)
+			++nc;
+	}
+
+	if (state == IN) {
+		i = nc - 1;
+		if (i > 9)
+			i = 9;
+		++ndigit[i];
+		nc = 0;
+	}
+
+	for (i = 0; i < 10; ++i) {
+		if (i == 9)
+			printf(" >9: ");
+		else
+			printf(" %2d: ", i + 1);
+		for (j = 0; j < ndigit[i]; ++j)
+			putchar('#');
+		putchar('\n');
+	}
+}