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-# Notes 01/13/2020
+Notes 01/13/2020
+
+> Review from COEN10
+# Pointers
+
+ int x;
+ x = 6;
+ int *px;
+ px = &x;
+
+- The pointer `*px` is "pointing" to the memory address where x is located (`&x`)
+- The pointer must be assigned a data type (in this case `int`) that matches the memory type that it is pointing to
+
+
+ x = 5;
+ *px = 1
+ printf("%d", x);
+
+
+- The code above will print `1` because `*px` (the value in the memory address that px is pointing to) was changed to 1, so x was changed to 1
+- You can change where the pointer is pointing to: `px++` changes the pointer to point to the next memory address
+ - This is useful when dealing with arrays:
+
+
+ int x[5] = {1, 2, 3, 4, 5}
+ int *px;
+ px = &x[0]; //can also be written px = x
+ printf("%d", *px);
+ px++;
+ printf("%d", *px);
+
+
+The code above would print `1` and then `px++` would move the pointer to point to `x[1]` and the second number printed would be `2`
+
+
+ int i;
+ px = &x[0];
+ for(i = 0; i < 5; i++){
+ printf("%d\n", *px);
+ px++;
+ }
+
+
+The code above would result in:
+
+
+ 1
+ 2
+ 3
+ 4
+ 5
+
+
+Another Example:
+
+
+ int x = 2, y = 2;
+ int *p, *q;
+ p = &y;
+ q = &y;
+ //(p == q) is false (comparison of addresses)
+ //(*p == *q) is true (comparison of values)
+
+
+Visual Representation of Memory:
+
+ int x[7] = {1, 2, 3, 4, 5, 6, 7};
+ int *px;
+ px = &x[0];
+
+`x[]` in memory
+
+| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+| - | - | - | - | - | - | - |
+| px | | | | | | |
+
+ px+=3;
+
+| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+| - | - | - | - | - | - | - |
+| | | | px | | | |
+
+---
+
+# Using Pointers with Strings
+
+Example:
+
+ char my_string[] = "String!"
+ char *p = my_string //Single line pointer definition. can also be written *p = &my_string[0]
+
+Visual Representation of `my_string[]` in memory:
+
+| S | T | R | I | N | G | ! | \0 |
+| - | - | - | - | - | - | - | - |
+| p | | | | | | | |
+
+We can print the string like this:
+
+ //don't need i
+ while(*p != '\0'){
+ printf("%c", *p);
+ p++;
+ }
+
+The above code would print `STRING!`
+
+---
+
+# Pointers and Functions
+
+- A function can also receive an array as an argument in the form of a pointer
+ - For Example:
+
+
+ void my_function(char *c){
+ ...
+ }
+
+
+- The function would receive a memory address pointing to a char. It would be beneficial to pass a memory address pointing to a string.
+ - Let's flesh-out the example:
+
+
+ void my_function(char *c){
+ printf("%s\n", *c);
+ c++;
+ printf("%s\n", *c);
+ }
+
+
+- Let's say we pass a memory address `&my_string[0]` and my_string is defined as `char my_string[] = "Hello World"`
+ - The code would output:
+
+
+ Hello World
+ ello World