add exercise 1-14: histogram of frequencies of characters

1 files changed, 30 insertions, 0 deletions

diff --git a/ch01/ex14-histogram.c b/ch01/ex14-histogram.c
new file mode 100644
index 0000000..6d410e1
--- /dev/null
+++ b/ch01/ex14-histogram.c
@@ -0,0 +1,30 @@
+#include <stdio.h>
+
+#define ASCII_FIRST_PRINTABLE_CODEPOINT 33
+#define ASCII_LAST_PRINTABLE_CODEPOINT  126
+#define ASCII_SPACE ASCII_LAST_PRINTABLE_CODEPOINT - ASCII_FIRST_PRINTABLE_CODEPOINT + 1
+
+#define BAR '#'
+
+/* print a histogram of the frequencies of different characters */
+int main()
+{
+	int c, i, j;
+	int nchar[ASCII_SPACE];
+
+	for (i = 0; i < ASCII_SPACE; ++i)
+		nchar[i] = 0;
+
+	while ((c = getchar()) != EOF)
+		if (c >= ASCII_FIRST_PRINTABLE_CODEPOINT && c <= ASCII_LAST_PRINTABLE_CODEPOINT)
+			++nchar[c - ASCII_FIRST_PRINTABLE_CODEPOINT];
+
+	for (i = 0; i < ASCII_SPACE; ++i) {
+		if (nchar[i] > 0) {
+			printf("%c: ", i + ASCII_FIRST_PRINTABLE_CODEPOINT);
+			for (j = 0; j < nchar[i]; ++j)
+				putchar(BAR);
+			putchar('\n');
+		}
+	}
+}