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14 Pointers

Among high-level languages, C is rather low-level, close to the machine. This is mainly because it has explicit pointers. A pointer value is the numeric address of data in memory. The type of data to be found at that address is specified by the data type of the pointer itself. Nothing in C can determine the “correct” data type of data in memory; it can only blindly follow the data type of the pointer you use to access the data.

The unary operator ‘*’ gets the data that a pointer points to—this is called dereferencing the pointer. Its value always has the type that the pointer points to.

C also allows pointers to functions, but since there are some differences in how they work, we treat them later. See Function Pointers.

• Address of Data
• Pointer Types
• Pointer-Variable Declarations
• Pointer-Type Designators
• Dereferencing Pointers
• Null Pointers
• Dereferencing Null or Invalid Pointers
• Void Pointers
• Pointer Comparison
• Pointer Arithmetic
• Pointers and Arrays
• Pointer Arithmetic at Low-Level
• Pointer Increment and Decrement
• Drawbacks of Pointer Arithmetic
• Pointer-Integer Conversion
• Printing Pointers