From e0ac6e6a3c74f0e4d5936462eaae4d450fa3ed43 Mon Sep 17 00:00:00 2001
From: Adam Carpenter <53hornet@gmail.com>
Date: Tue, 14 May 2019 11:40:11 -0400
Subject: Finished functions.

---
 charhist.c | 30 ++++++++++++++++++++++++++++++
 ctof.c     | 20 ++++++++++++++++----
 ftoc.c     | 13 +++++++++----
 power.c    | 28 ++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+), 8 deletions(-)
 create mode 100644 charhist.c
 create mode 100644 power.c

diff --git a/charhist.c b/charhist.c
new file mode 100644
index 0000000..312df76
--- /dev/null
+++ b/charhist.c
@@ -0,0 +1,30 @@
+#include<stdio.h>
+
+#define CHARSET_LENGTH 128;
+
+/*
+ * Prints a histogram of the lengths of words in its input.
+ */
+main() {
+    int c, i;
+    int count;
+    int length = CHARSET_LENGTH;
+    int c_counts[length];
+
+    for (i = 0; i < length; ++i) {
+        c_counts[i] = 0;
+    }
+
+    while ((c = getchar()) != EOF) {
+        ++c_counts[c];
+    }
+
+    for (i = 0; i < length; ++i) {
+        count = c_counts[i];
+
+        if (count > 0 && (i != ' ' && i != '\t' && i != '\n' )) {
+            printf("%c\t", i);
+            printf("%d\n", count);
+        }
+    }
+}
diff --git a/ctof.c b/ctof.c
index 7e2cbef..b95e20a 100644
--- a/ctof.c
+++ b/ctof.c
@@ -1,5 +1,11 @@
 #include<stdio.h>
 
+#define LOWER 0;
+#define UPPER 300;
+#define STEP 20;
+
+float ctof(int c);
+
 /*
  * Print Celcius-Fahrenheit table for celcius = 0, 20, ... 300.
  */
@@ -7,18 +13,24 @@ main() {
     float fahr, celcius;
     int lower, upper, step;
 
-    lower = 0;      // lower limit of temperature table
-    upper = 300;    // upper limit of temperature table
-    step = 20;      // step size
+    lower = LOWER;      // lower limit of temperature table
+    upper = UPPER;    // upper limit of temperature table
+    step = STEP;      // step size
 
     celcius = lower;
 
     printf("%3s %6s\n", "C", "F");
 
     while (celcius <= upper) {
-        fahr = (9.0 / 5.0) * celcius + 32.0;
+        fahr = ctof(celcius);
         printf("%3.0f %6.1f\n", celcius, fahr);
         celcius = celcius + step;
     }
 }
 
+/*
+ * Convert Celcius to Fahrenheit
+ */
+float ctof(int celcius) {
+    return (9.0 / 5.0) * celcius + 32.0;
+}
diff --git a/ftoc.c b/ftoc.c
index 2efa6f7..70b994a 100644
--- a/ftoc.c
+++ b/ftoc.c
@@ -4,6 +4,8 @@
 #define     UPPER   300     // upper limit of table 
 #define     STEP    20      // step size
 
+float ftoc(int fahr);
+
 /*
  * Print Fahrenheit-Celcius table for fahr = 0, 20, ... 300.
  */
@@ -11,9 +13,9 @@ main() {
     float fahr, celcius;
     int lower, upper, step;
 
-    lower = 0;      // lower limit of temperature table
-    upper = 300;    // upper limit of temperature table
-    step = 20;      // step size
+    lower = LOWER;      // lower limit of temperature table
+    upper = UPPER;    // upper limit of temperature table
+    step = STEP;      // step size
 
     fahr = lower;
 
@@ -26,7 +28,10 @@ main() {
     //    }
 
     for (fahr = UPPER; fahr >= LOWER; fahr = fahr - STEP) {
-        printf("%3.0f %6.1f\n", fahr, (5.0 / 9.0) * (fahr - 32));
+        printf("%3.0f %6.1f\n", fahr, ftoc(fahr));
     }
 }
 
+float ftoc(int fahr) {
+    return (5.0 / 9.0) * (fahr - 32);
+}
diff --git a/power.c b/power.c
new file mode 100644
index 0000000..8bca4fd
--- /dev/null
+++ b/power.c
@@ -0,0 +1,28 @@
+#include<stdio.h>
+
+int power(int m, int n);
+
+/*
+ * Test power function
+ */
+main() {
+    int i;
+
+    for (i = 0; i < 10; ++i)
+        printf("%d %d %d\n", i, power(2, i), power(-3, i));
+
+    return 0;
+}
+
+/*
+ * 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;
+}
-- 
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