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Call by Value vs. Call by Reference: What's the Difference?

Edited by Huma Saeed || By Sawaira Riaz || Published on February 5, 2024
Call by value copies the actual value of an argument into the formal parameter of the function, whereas call by reference passes the argument's address, allowing direct modification of the original variable.

Key Differences

Call by value in programming means that when a function is called, the values of the actual parameters are copied into the function's formal parameters. In call by reference, instead of values, the addresses of the actual parameters are passed, linking the formal and actual parameters.
Sawaira Riaz
Feb 05, 2024
With call by value, modifications made to the formal parameters in the function do not affect the actual parameters. In contrast, call by reference allows the function to modify the actual parameters since the formal parameters reference the actual memory locations.
Huma Saeed
Feb 05, 2024
Call by value is generally safer as it protects the actual parameters from unintended changes. Call by reference, being more memory-efficient, can lead to unintentional side effects if the function alters the value of the referenced variable.
Sawaira Riaz
Feb 05, 2024
In languages that support both methods, call by value is typically used when the integrity of the original data is paramount. Call by reference is preferred for large data structures or objects where copying values would be inefficient.
Sawaira Riaz
Feb 05, 2024
Call by value results in additional memory usage due to duplication of values, which can be a drawback for large data. Call by reference, while conserving memory, requires careful handling to prevent errors due to the direct manipulation of variables.
Janet White
Feb 05, 2024
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Comparison Chart

Parameter Passing

Copies actual value
Passes address of the variable
Sawaira Riaz
Feb 05, 2024

Memory Usage

More, due to duplication
Less, no duplication
Sawaira Riaz
Feb 05, 2024

Effect on Original Variable

No change to the original variable
Can modify the original variable
Sawaira Riaz
Feb 05, 2024

Safety

Safer, no unintended side effects
Risk of side effects
Janet White
Feb 05, 2024

Use Case

Used when data integrity is important
Used for efficiency with large data structures
Sawaira Riaz
Feb 05, 2024
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Call by Value and Call by Reference Definitions

Call by Value

Uses more memory due to value duplication.
Call by value is less memory efficient due to creating copies of arguments.
Harlon Moss
Jan 22, 2024

Call by Reference

Passes the address of an argument to a function.
With call by reference, changes in the function affect the original variable.
Sawaira Riaz
Jan 22, 2024

Call by Value

Protects the original data from modification.
Call by value is used to ensure the actual argument remains unchanged.
Sawaira Riaz
Jan 22, 2024

Call by Reference

Can lead to unintended side effects.
Care must be taken with call by reference to prevent accidental data modification.
Sawaira Riaz
Jan 22, 2024

Call by Value

Copies the value of an argument into a function.
In call by value, modifying a parameter inside the function doesn’t alter the original argument.
Sawaira Riaz
Jan 22, 2024

Call by Reference

Function can modify the original data.
Call by reference allows the function to directly update the argument's value.
Sawaira Riaz
Jan 22, 2024

Call by Value

Function works with a copy of the argument.
Using call by value, the function's actions remain local to that function only.
Huma Saeed
Jan 22, 2024

Call by Reference

More memory efficient, avoids duplication.
Using call by reference is preferred for large objects due to its memory efficiency.
Sawaira Riaz
Jan 22, 2024

Call by Value

Safe method preventing side effects.
Call by value is chosen to avoid unintended changes to variables.
Harlon Moss
Jan 22, 2024

Call by Reference

Suitable for large data structures.
Call by reference is used for efficient processing of large arrays.
Sawaira Riaz
Jan 22, 2024

Call by Value

(programming) An evaluation strategy in which the arguments to a function are evaluated first, and the result is passed into the function.
Sawaira Riaz
Jan 22, 2024

Call by Reference

(programming) An evaluation strategy in which the arguments to a function are evaluated first, and a pointer to the result is passed to the function.
Sawaira Riaz
Jan 22, 2024

FAQs

Can call by reference modify the original data?

Yes, it directly modifies the original variable.
Harlon Moss
Feb 05, 2024

What is call by value in programming?

A method where the actual value of an argument is passed to a function.
Sawaira Riaz
Feb 05, 2024

What does call by reference mean?

Passing the address of an argument to a function, allowing direct modification.
Huma Saeed
Feb 05, 2024

How does call by value affect the original variable?

It does not affect the original variable; changes are made to the copy.
Sawaira Riaz
Feb 05, 2024

When should call by value be used?

When data integrity and protection from modification are important.
Janet White
Feb 05, 2024

What type of data is best suited for call by reference?

Large data structures like arrays or objects.
Janet White
Feb 05, 2024

Is call by value safer than call by reference?

Yes, because it doesn't risk altering the original data.
Sawaira Riaz
Feb 05, 2024

Why is call by reference more memory efficient?

It avoids duplicating large data structures by passing addresses.
Janet White
Feb 05, 2024

Does call by value have a performance impact?

It can, especially with large data due to copying overhead.
Sawaira Riaz
Feb 05, 2024

Does call by value work well with small data types?

Yes, as the overhead of copying small data is negligible.
Janet White
Feb 05, 2024

Can call by value be used for efficiency?

Not typically, as it involves additional memory use for copying.
Harlon Moss
Feb 05, 2024

What is a common use of call by reference?

Efficiently passing and modifying large data structures.
Aimie Carlson
Feb 05, 2024

Can functions using call by reference create side effects?

Yes, due to the direct manipulation of variables.
Janet White
Feb 05, 2024

Are primitive data types typically passed by value?

Yes, primitives are often passed by value in many programming languages.
Harlon Moss
Feb 05, 2024

Is call by reference available in all programming languages?

No, some languages only support call by value.
Sawaira Riaz
Feb 05, 2024

How do you implement call by reference?

By passing pointers or references to variables.
Aimie Carlson
Feb 05, 2024

Is the original variable accessible in call by value?

No, only its copy is accessible within the function.
Harlon Moss
Feb 05, 2024

How does call by reference affect function arguments?

Arguments can be changed within the function, reflecting in the original.
Aimie Carlson
Feb 05, 2024

Can call by value and call by reference be mixed?

Yes, depending on the language and function design.
Aimie Carlson
Feb 05, 2024

Why might call by reference be risky?

Because it can unintentionally alter the state of variables.
Aimie Carlson
Feb 05, 2024
About Author
Written by
Sawaira Riaz
Sawaira is a dedicated content editor at difference.wiki, where she meticulously refines articles to ensure clarity and accuracy. With a keen eye for detail, she upholds the site's commitment to delivering insightful and precise content.
Edited by
Huma Saeed
Huma is a renowned researcher acclaimed for her innovative work in Difference Wiki. Her dedication has led to key breakthroughs, establishing her prominence in academia. Her contributions continually inspire and guide her field.

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