commit2

.vscode/settings.json

+{
+    "files.associations": {
+        "stdio.h": "c"
+    }
+}
\ No newline at end of file

arrayboundaryoverrun.c

+//  Ex 4
+#include <stdio.h>
+
+int main(void) {
+
+int a[] = {1,1,1,1};
+int b[] = {2,2,2,2};
+
+for (int i=0;i<4;i++)
+{
+  printf("array a[%d] %d at address %p\n",i,a[i], &a[i]);
+}
+printf("\n");
+
+for (int i=0;i<4;i++)
+{
+  printf("array b[%d] %d at address %p\n",i,b[i], &b[i]);
+}
+printf("\n");
+
+for (int i=0; i<8; i++)
+{
+  b[i]=3;
+  printf("setting array b[%d] to %d at address %p\n",i,b[i], &b[i]);
+}
+printf("\n");
+
+for (int i=0;i<4;i++)
+{
+  printf("array a[%d] %d at address %p\n",i,a[i], &a[i]);
+}
+printf("\n");
+
+for (int i=0;i<4;i++)
+{
+  printf("array b[%d] %d at address %p\n",i,b[i], &b[i]);
+}
+printf("\n");
+
+
+return 0;
+}
+
+// Task Exercises
+// 1 Resize the a[] array to store six integers and set them all to 1. Change the loops printing out a[] to match. Run the code - what is the effect?
+// 2 Resize the b[] array to store six integers and set them all to 2. Change the loops printing out b[] to match. Run the code - what is the effect? Why is a[] now unaffected by overrunning b[]?
+// 3 Change the loop that sets b[] to 3 from i<8 to i<10. Run the code. Does a[] change at all now?
+// 4 Create a new array c[] immeadiately after creating b[]. Make it four long and set each value in it to 4. Print out all of c[] after printing out b[] each time. Run the code. Does c[] change?
+// 5  Change the loop that sets b[] to 3 from int i=0 to int i=-2. Run the code. Does c[] change at all now? Why?

memoryaddresses.c

+//  Ex 1
 #include <stdio.h>
 #include <stdalign.h>
 
 int main(void) {
 
-int integer1=1;
-short short2=2;
-int integer3=3;
-char char1=4;
-float float1=3.14;
+int integer1 = 1;
+short short2 = 2;
+int integer3 = 3;
 
+char char1 = 4;   //2
+float float1 = 3.14;  //2
 
-printf("integer1 =%d Memory address%p\n",integer1,&integer1);
-printf("short2 =%d Memory address%p\n",short2,&short2);
-printf("integer3 =%d Memory address%p\n",integer3,&integer3);
+printf("integer1 =%d Memory address%p\n",integer1, &integer1);
+printf("size= %d\n", sizeof(integer1));
+printf("short2 =%d Memory address%p\n",short2, &short2);
+printf("integer3 =%d Memory address%p\n",integer3, &integer3);
 printf("char1 = %d Memory address%p\n", char1, &char1);
 printf("float1 = %d Memory address%p\n", float1, &float1);
 
+
 // Exercise Tasks
 // 1 Run this code and take note of the addresses. Run it again and compare the addresses.
 
@@ -33,8 +36,10 @@ printf("float1 = %d Memory address%p\n", float1, &float1);
 
 // 3 Extend each printf to also print out the size of each variable type.
 
+
 // 4 Rearrange the variable declaration order and see if it has an effect on the addresses
 
+
 //   You may want to rearrange your printfs to match the order of your declarations
 
 

pointerchecking.c

+//  Ex 3
+#include <stdio.h>
+
+int main () {
+
+  int var = 20;       
+  int *ip1 = &var;    
+  int *ip2;
+  return 0;
+}
+
+// Exercise Tasks
+// 1 Run the code. What is ip2 pointing at? Is this safe?
+// 2 ip2 might be pointing at an integer. Print out the value ip2 is pointing at as an integer
+// 3 Initialise ip2 to NULL. Comment out the line printing out ip2 as an integer. Run the code.
+// 4 Uncomment the line you just commented out and run the code. Why doe s the code crash?
+// 5 Add checks before trying to use ip1 or ip2, test to make sure they are not NULL before accessing them.
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pointers.c

+//  Ex 2
+#include <stdio.h>
+
+int main () {
+
+  int var = 20;   
+
+  // Exercise tasks
+  // 1 Create a pointer variable that stores the address of var
+  // 2 Print out the address of var using &var
+  // 3 Print out the value stored in your pointer, ensure it is the same as the address from &var
+  // 4 Print out the value of var
+  // 5 Print out the value your pointer is pointing to using the * redirector
+  // 6 After your printfs change the value stored in var using var =  and output the four printfs from 2-6 again. 
+  // 7 Now change the value using your pointer and the * redirection. Again output the four printfs after to see what has changed.
+
+  return 0;
+}
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