Diff: main.cpp

Revision:

0:78eefa5ae28e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Oct 06 03:20:11 2017 +0000
@@ -0,0 +1,62 @@
+/*
+ Program 8.3 Calculating an average using functions.
+ from Horton's Beginning C, 5th ed.
+
+ Note isolation of user input in main and a single function.
+
+ Ported to mbed by C. S. Tritt
+ Last revised: 10/5/17 (v. 1.0)
+*/
+#include "mbed.h"
+
+const int MAX_COUNT=10; // Set input limit. Protects against buffer overrun.
+
+// Function prototypes...
+float Sum(float x[], int n); // Sums the values in a float array.
+float Average(float x[], int n); // Averages the values in a float array.
+int GetData(float *data, int max_count); // Gets data from std Serial.
+
+// main program - execution starts here.
+int main(void) {
+    float samples[MAX_COUNT] = {0.0};  // Create array for samples.
+    int sampleCount = GetData(samples, MAX_COUNT); // Get values.
+    float average = Average(samples, sampleCount); // Find average.
+    // Display results.
+    printf("The average of the values you entered is: %.2f.\n", average);
+    return 0;
+}
+
+// Function to calculate the sum of array elements. n is the number of elements
+// in array x.
+float Sum(float x[], int n) {
+    float sum = 0.0;
+    for(int i = 0 ; i < n ; ++i) sum += x[i];
+    return sum;
+}
+
+// Function to calculate the average of array elements. Calls Sum.
+float Average(float x[], int n) {
+    return Sum(x, n)/n;
+}
+
+// Function to read in data items and store in data array. The function returns
+// the number of items stored.
+int GetData(float *data, int max_count) {
+    int nValues = 0;
+    // Clear screen & move cursor to upper left ANSI/VT100 sequence.
+    const char ESC=27; printf("%c[2J", ESC); printf("%c[H", ESC);
+    printf("Assure Local Echo is activated!\n");
+    printf("Number of values to average (Maximum %d)? ", max_count);
+    scanf("%d", &nValues);
+    printf("%d was read.\n", nValues); // added by cst.
+    if(nValues > max_count) {
+        printf("Maximum count exceeded. %d items will be read.", max_count);
+        nValues = max_count;
+    }
+    printf("Enter values:\n");
+    for( int i = 0 ; i < nValues ; ++i) {
+        scanf("%f", &data[i]);
+        printf("%f was read.\n", data[i]); // added by cst.
+    }
+    return nValues;
+}
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