cplusplus:pointers_3
Differences
This shows you the differences between two versions of the page.
| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| cplusplus:pointers_3 [2014/04/28 23:46] – mithat | cplusplus:pointers_3 [2016/03/05 23:27] (current) – [Pointers 3] mithat | ||
|---|---|---|---|
| Line 1: | Line 1: | ||
| ====== Pointers 3 ====== | ====== Pointers 3 ====== | ||
| - | Pointers, arrays, arithmetic.((Portions loosely adapted from: FIXME)) | + | Pointers, arrays, arithmetic. |
| ===== Pointers and arrays ===== | ===== Pointers and arrays ===== | ||
| - | Arrays and pointers in C++ are very closely related. In C++ an array name is like a constant pointer: the block of memory where array name points cannot be changed, but what is stored there can change. | + | Arrays and pointers in C++ are very closely related. In C++ an array name is like a constant pointer: the block of memory where an array name points cannot be changed, but what is stored there can change. |
| The relationship is so close that you can use pointer operators with array names: | The relationship is so close that you can use pointer operators with array names: | ||
| Line 39: | Line 39: | ||
| C++ lets you perform arithmetic on pointer variables; however, //pointer arithmetic works differently from normal arithmetic!// | C++ lets you perform arithmetic on pointer variables; however, //pointer arithmetic works differently from normal arithmetic!// | ||
| - | In other words, adding 1 to a pointer makes it to point to the next block of memory corresponding to the size of the underlying type and subtracting 1 from a pointer makes to point to the previous block of memory corresponding to the size of the underlying type. This is really only meaningful when performed on an array. | + | In other words, adding 1 to a pointer makes it point to the next block of memory corresponding to the size of the underlying type; subtracting 1 from a pointer makes it point to the previous block of memory corresponding to the size of the underlying type. This is really only meaningful when performed on an array. |
| <file cpp pointer-math.cpp> | <file cpp pointer-math.cpp> | ||
| + | /** Pointer arithmetic. */ | ||
| #include < | #include < | ||
| using namespace std; | using namespace std; | ||
| Line 65: | Line 66: | ||
| Subtracting one pointer from another returns the number of elements between two addresses: | Subtracting one pointer from another returns the number of elements between two addresses: | ||
| - | <file cpp pointer-subtraction.cpp> | + | <file cpp subtracting-pointers.cpp> |
| + | /** Subtracting pointers */ | ||
| #include < | #include < | ||
| using namespace std; | using namespace std; | ||
| Line 83: | Line 85: | ||
| ==== Walking down an array ==== | ==== Walking down an array ==== | ||
| - | A common technique used to visit every element in an array is to //walking | + | A common technique used to visit every element in an array is to //walk down an array// with a pointer: |
| <file cpp walk-down-array.cpp> | <file cpp walk-down-array.cpp> | ||
| + | /** Walking down an array. */ | ||
| #include < | #include < | ||
| using namespace std; | using namespace std; | ||
| Line 94: | Line 97: | ||
| int *vPtr = v; | int *vPtr = v; | ||
| - | for(int i=0; i<5; i++) | + | for (int i = 0; i < 5; i++) |
| { | { | ||
| cout << *vPtr << endl; | cout << *vPtr << endl; | ||
| Line 107: | Line 110: | ||
| <file cpp walk-null-terminated.cpp> | <file cpp walk-null-terminated.cpp> | ||
| + | /** Walking down a null-terminated array. */ | ||
| #include < | #include < | ||
| using namespace std; | using namespace std; | ||
| Line 146: | Line 150: | ||
| ^ Operation | ^ Operation | ||
| - | |< | + | |Increment |
| - | |< | + | |Decrement |
| - | |< | + | |Arithmetic |
| - | |< | + | |Compound assignment |
| valptr += 2; // points at 11</ | valptr += 2; // points at 11</ | ||
| - | |< | + | |Pointer subtraction |
cplusplus/pointers_3.1398728774.txt.gz · Last modified: 2014/04/28 23:46 by mithat