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Anonymous Struct and Union

The C programming language has anonymous structures and unions, which provide the ability to define structures and unions without specifying a name.


python


python

Since there are no names, direct objects (or variables) are not created from them we use them as nested structures or unions.

You can use anonymous structs/unions when they are nested and will only be used where they are declared.

main


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#include <stdio.h>

struct ASCIItable {
    // Anonymous union
    union {
        char symbol;
        int num;
    };
};

int main()
{
    struct ASCIItable AZtable;
    AZtable.num = 65;

     // number 65 is first symbol `A`,
     // number 97 is last `Z` symbol, hence 97 - 65 = 25, 
     // so 26 iterations required (including number 0)

    for (int i = 0; i < 26; i++)
        printf("x.num = %d | x.symbol = `%c`\n", AZtable.num + i, AZtable.symbol + i);

    return 0;
}

Note

Union allows the same set of bits to be represented differently depending on the context. For example, in an ASCIItable structure, you can interpret the same value as a character (using symbol) or as a numeric value (using num). This can be useful when you need to quickly switch between different data views.

Task

Swipe to start coding

Create an anonymous structure;
Declare three float fields in it with the names x, y, radius;
Define the fields of the structure instance;
Display the values of the structure fields.

Solution

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Section 4. Chapter 3

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Anonymous Struct and Union

The C programming language has anonymous structures and unions, which provide the ability to define structures and unions without specifying a name.


python


python

Since there are no names, direct objects (or variables) are not created from them we use them as nested structures or unions.

You can use anonymous structs/unions when they are nested and will only be used where they are declared.

main


              123456789101112131415161718192021222324
            
#include <stdio.h>

struct ASCIItable {
    // Anonymous union
    union {
        char symbol;
        int num;
    };
};

int main()
{
    struct ASCIItable AZtable;
    AZtable.num = 65;

     // number 65 is first symbol `A`,
     // number 97 is last `Z` symbol, hence 97 - 65 = 25, 
     // so 26 iterations required (including number 0)

    for (int i = 0; i < 26; i++)
        printf("x.num = %d | x.symbol = `%c`\n", AZtable.num + i, AZtable.symbol + i);

    return 0;
}

Note

Union allows the same set of bits to be represented differently depending on the context. For example, in an ASCIItable structure, you can interpret the same value as a character (using symbol) or as a numeric value (using num). This can be useful when you need to quickly switch between different data views.

Task

Swipe to start coding

Create an anonymous structure;
Declare three float fields in it with the names x, y, radius;
Define the fields of the structure instance;
Display the values of the structure fields.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 3

Switch to desktop for real-world practiceContinue from where you are using one of the options below