Engineering Science 1036A/B Lecture 23: Pointers: References vs. Pointers
10 May 2018
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References
References are simpler, but restricted
Can only point to one object during its lifetime
must be initialized at the time of declaration
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Cannot do any arithmetic
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Used as an alias to another object
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Declaring
int a;
int &b = a;
means &b=&a
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bbecomes an alias of a
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Grammar: reference variable must be initialized at the declaration statement
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Using
int a;
int &b = a;
b = 5;
cout << b++ << endl; cout<< a << endl;
The following will result in a syntactical error:
int a;
int &b;
compilation error
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b = a;
int &c = &a
compilation error
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Grammar: Arrays of references are illegal
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Pointers
Pointers are powerful and more complex
Can point to different objects during its lifetime
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Can do “pointer arithmetic”
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Uses additional syntax
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Declaring
int *ptr_a;
int b, *iptr;
Using
iptr = &b;
Assign
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*iptr = 5;
Use
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cout << b << *iptr;
cout << iptr;
Call by Reference using referenced variables
after the call: int &x=a (&x=&a) and int &y=b (&y=&b)
x and y become the aliases of a and b
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References vs. Pointers
