Chapter 4 Parameters 1 Parameters T wo methods of passing - - PowerPoint PPT Presentation
Chapter 4 Parameters 1 Parameters T wo methods of passing arguments to parameters Call-by-value Also called Pass-by-value copy of value is passed Call-by-reference Also called Pass-by-reference address of
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– Also called Pass-by-value – “copy” of value is passed
– Also called Pass-by-reference – “address of” argument is passed – Cannot be used when passing literals
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– Function has no access to “actual argument”
from caller
– Used in all examples so far
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– T
– Data is then “given” to caller
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– Reference to memory location of argument – Called “memory address” – Unique number referring to a distinct place in
memory
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– Caller's data can be changed – Often this is desired, sometimes not
– Use const keyword – No copy is made, only reference is passed – Argument is now read-only
void displayData(const int& value1, const int& value2);
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– Pass-by-value – Pass-by-reference – Const pass-by reference
– Pay attention to the order defined in the
function header
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– Must be meaningful – Should reflect its use
– Designed separately from rest of program – Parameter names can be same as argument
names