Differences

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--- cplusplus:pointers_4_slides [2019/03/31 22:36] – mithat
+++ cplusplus:pointers_4_slides [2021/10/24 03:02] – [''malloc'' and ''free''] mithat
@@ Line 17: / Line 17: @@
     * reserves a block of memory to hold the specified %%<data-type>%%
     * returns the base address of that block.
+    * optional parenthesis around ''<data-type>''
 <code cpp>
@@ Line 25: / Line 26: @@
 </code>
-  * ''foo'' points to a ''double'' that is not associated with a regular variable identifier.
+  * ''foo'' points to a ''double'' that isn't associated with a variable identifier.
 ===== Example =====
@@ Line 38: / Line 39: @@
     double *myPtr, *yourPtr;
-    myPtr = new (double);
+    myPtr = new double;
-    yourPtr = new (double);
+    yourPtr = new double;
     cout << "Enter a number: ";
@@ Line 108: / Line 109: @@
 void ninetynine()
 {
-    int localVar = 99;
+    int localVar = 99;  // localVar is destroyed at end of fcn call
     cout << localVar << endl;
 }
@@ Line 138: / Line 139: @@
 void ninetynine()
 {
-    int *localPtr = new int;
+    int *localPtr = nullptr;  // localPtr is destroyed at end of fcn call
+    localPtr = new int;       // but not dynamically allocated storage
     *localPtr = 99;
@@ Line 182: / Line 184: @@
   * Memory leaks, no matter how small, are bad programming practice.
   * Can be fixed by the proper use of **deallocation**: releasing back to the OS storage that was previously dynamically allocated.
-  * Deallocation of dynamically allocated storage does not happen automatically.
+  * **Deallocation of dynamically allocated storage does not happen automatically.**
     * You must explicitly (i.e., manually) deallocate the memory.
@@ Line 191: / Line 193: @@
 int *myPtr = new int;
 ...
-delete myPtr; // deallocates block pointed to by localPtr.
+delete myPtr; // deallocates block pointed to by myPtr.
 </code>
@@ Line 239: / Line 241: @@
 int main()
 {
-    double *sales = nullptr,	// To dynamically allocate an array
+    double *sales = nullptr,    // To dynamically allocate an array
-    total = 0.0,				// Accumulator
+    total = 0.0,                // Accumulator
-    average;					// To hold average sales
+    average;                    // To hold average sales
-    int numDays,				// To hold the number of days of sales
+    int numDays,                // To hold the number of days of sales
-        count;					// Counter variable
+        count;                  // Counter variable
     // Get the number of days of sales.
@@ Line 296: / Line 298: @@
   * ''malloc'' and ''free'' can also used be used to allocate and deallocate storage.
   * Part of C and so are available in C++ as well.
-  * More cumbersome than ''new'' and ''delete'', and their use is discouraged.
+  * More cumbersome than ''new'' and ''delete'', so their use is discouraged.
 ===== Returning Pointers from Functions =====