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--- cplusplus:repetition_examples [2013/03/01 01:10] – mithat
+++ cplusplus:repetition_examples [2019/02/14 21:27] – [Counter-controlled repetition] mithat
@@ Line 1: / Line 1: @@
 ====== Control Structures: Repetition examples ======
-===== while =====
+===== The while statement =====
 <file c++ simple_while.cpp>// This program counts to an upper limit
@@ Line 34: / Line 34: @@
     cout << num << endl;
     num++;
-    cout << num << endl;
     return 0;
@@ Line 40: / Line 39: @@
 </file>
-===== Sentinel-controlled repetition =====
-<file c++ simple-sentinel.cpp>// This program calculates the squares of integers. The user
+===== Repetition code patterns =====
-// enters -999 when finished.
+==== Counter-controlled repetition ====
+<file c++ counter-controlled-repetition.cpp>// This program counts to an upper limit
 #include <iostream>
 using namespace std;
@@ Line 49: / Line 49: @@
 int main()
 {
-    int num = 1;
+    const int UPPER_LIMIT = 5;
+    int num = 1;                 // initialize the counter
-    cout << "Enter an integer and I will tell you its square. " << endl;
+    while (num <= UPPER_LIMIT)   // test the count
-    cout << "Enter -999 to quit: ";
+    {
+        cout << num << endl;
+        num++;                   // increment the counter
+    }
+    return 0;
+}</file>
+==== Sentinel-controlled repetition ====
+<file c++ simple-sentinel.cpp>    // This program determines whether test scores are passing marks.
+    #include <iostream>
+    using namespace std;
+    int main()
+    {
+        const unsigned int PASSING_SCORE = 60;
+        int score;
+        cout << "Enter a test scrore and I will tell you if it is a passing mark." << endl;
+        cout << "Enter -1 to quit: ";
+        cin >> score;
+        while (score != -1)
+        {
+            if (score >= PASSING_SCORE)
+            {
+                cout <<  score << ": PASS" << endl;
+            }
+            else
+            {
+                cout <<  score << ": FAIL" << endl;
+            }
+            cout << "Enter a test scrore and I will tell you if it is a passing mark." << endl;
+            cout << "Enter -1 to quit: ";
+            cin >> score;
+        }
+        return 0;
+    }
+</file>
+==== Input validation ====
+<file c++ simple-input-validation.cpp>// Simple example of input validation.
+#include <iostream>
+using namespace std;
+int main()
+{
+    const int LOWER_BOUND = 0;
+    const int UPPER_BOUND = 100;
+    int num;
+    cout << "Enter a number between " << LOWER_BOUND
+         << " and " << UPPER_BOUND << ": ";
     cin >> num;
-    while (num != -999)
+    // Fall through loop only if input is valid.
+    while (num < LOWER_BOUND || num > UPPER_BOUND)
     {
-        cout << num <<" squared is " << num * num << "." << endl
+        cout << "Enter a number between " << LOWER_BOUND
-             << endl;
+             << " and " << UPPER_BOUND << ": ";
-        cout << "Enter an integer and I will tell you its square. " << endl;
-        cout << "Enter -999 to quit: ";
         cin >> num;
     }
+    cout << "Congratulations, you can follow directions." << endl;
     return 0;
-}</file>
+}
+</file>
+==== Running total ====
+<file c++ simple-running-total.cpp>// Simple running total example.
+// Total all the integers between a lower and an upper bound.
+#include <iostream>
+using namespace std;
+int main()
+{
+    const int LOWER_BOUND = 0;
+    const int UPPER_BOUND = 10;
+    int num = LOWER_BOUND;  // counter
+    int sum = 0;            // accumulator
+    while (num <= UPPER_BOUND)
+    {
+        sum += num;         // add the new value to the sum
+        num++;
+    }
+    cout << "The sum of integers from " << LOWER_BOUND
+         << " to " << UPPER_BOUND
+         << " is " << sum << endl;
+    return 0;
+}
+</file>
-===== for =====
+===== The for statement =====
-<file c++ simple-for.cpp>// This program counts to an upper limit
+<file c++ simple-for.cpp>// This program counts to an upper limit using a for structure.
-// using a for structure.
 #include <iostream>
 using namespace std;
@@ Line 128: / Line 216: @@
         cin >> choice;
         if (choice == 'N' || choice == 'n')
-            break;    // (try replacing with continue)
+            break;    // (try replacing with 'continue')
         num++;
     }