Pointers are memory address for variables. Therefore pointers references to other variables.
Pointers indicate where (i.e. what memory address) the variables they reference are.
Declaring pointer variables
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Syntax: type *variablename;
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Examples:
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int *intPtr;
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double *myPtr;
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char *cp;
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float *arrayOfPtrs[10]; // an array of ten pointers to float objects
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char **arguments; // a pointer-to-a-pointer-to characters
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Pointers can also be initialized at declaration time. For example:
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float *fPtr = NULL;
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int i = 10; int *ip = &i;
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char name[] = "Jim"; char *cPtr = name;
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Pointer-related operators: "*" and "&"
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The operator "*" has two uses:
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In a declaration, *, is used to indicate that a variable is a pointer.
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In an assignment statement, *, is used to dereference the pointer, e.g.,
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ip is the memory address of i, *ip is the value at the memory address, i.e., 10.
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The operator "&" is the address of operator (see example declaration above)
Working with pointers
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When we work with other variables we generally have written them as boxes with values inside to represent that variables are named memory which can hold information. For example:
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int i = 7; can be represented as
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double d = 23.4 as
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int
ip = &i;
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The new operator
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The new operator provides for storage from a place called the dynamic storage pool or heap
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Example: ip = new int; or ip = new int[10]; The first gives you space for one int, the second space for 10 int
The delete operator
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The delete operator lets the memory management system know you are finished using the storage which was allocated with new.
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Example: To return the storage assigned to ip in the example above use: delete ip; (in the first case, because there is only one int to return) or delete [] ip; (in the second case, because you have an array of 10 int to return)
Examples: