operatori + analog

[sketchbook_andrea] / programming / pointers_c / pointers_3_resetting_before_use / pointers_3_resetting_before_use.ino

diff --git a/programming/pointers_c/pointers_3_resetting_before_use/pointers_3_resetting_before_use.ino b/programming/pointers_c/pointers_3_resetting_before_use/pointers_3_resetting_before_use.ino
new file mode 100644 (file)
index 0000000..02642eb
--- /dev/null
+++ b/programming/pointers_c/pointers_3_resetting_before_use/pointers_3_resetting_before_use.ino
@@ -0,0 +1,49 @@
+/*
+Purpose: Illustrate pointer arithmetic
+ Dr. Purdum, August 20, 2012
+ */
+#include <string.h>
+void setup() {
+  Serial.begin(9600);
+}
+void loop() {
+  char buffer[50];
+  char *ptr;
+  int i;
+  int length;
+
+  strcpy(buffer, "When in the course of human events");
+  ptr = buffer;
+  length = strlen(buffer);
+  Serial.print("The lvalue for ptr is: ");
+  Serial.print((unsigned int)&ptr);
+  Serial.print(" and the rvalue is ");
+  Serial.println((unsigned int)ptr);
+  while (*ptr) {
+    Serial.print(*ptr++); // This actually incrementa ptr* + 34
+  }
+  Serial.println("");
+
+  Serial.println("Lenght of the string is: ");
+  Serial.println(length);  
+  Serial.println("");
+
+
+  // ptr = ptr - length ; // Whis would roll back ptr
+  for (i = 0; i < length; i++) {
+    Serial.print(*(ptr + i));  
+    // Serial.print(*(ptr + i- lenght)); // ptr is one lenght up ahead
+  }
+  // ptr = buffer  ;    // Right thing to do: reset the pointer before use
+  //   for (i = 0; i < length; i++) {
+  // Serial.print(*(ptr + i))
+
+
+  Serial.flush();
+  // Make sure all the data is sent...
+  exit(0);
+}
+
+
+
+