How to create a struct and its object in C

Syntax of 'struct'

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//Defining a struct

struct StructName {

    dataType member1;

    dataType member2;

    ...

};

​

//Declaring Variables/object of a struct

​

struct StructName variableName;

​

​

• struct StructName: The 'struct' keyword defines the 'struct'. The 'StructName' is the name of the structure and it will be replaced by the user defined name.
• dataType member1;: The 'dataType' is the data type of the member (variable) of structure and the 'member1' is name of the member (variable) of the structure. The 'member1' will be replaced by the user defined name.
• struct StructName variableName;: The 'struct' is the keyword and 'StructName' is the name of the struct. 'StructName' will be followed by the 'variableName' and it will be replaced by the user defined variable name.

Create a 'struct'

A 'struct' and it object have been created in the following example:

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#include <stdio.h>

#include <string.h> // This directive is used for 'strcpy' function

    //Defining a struct

    struct Person {

    char name[50];

    int age;

    };

​

int main() {

    //Declaring variable of Person Struct   

    struct Person personObj;

​

    //Initializing member variables of personObj

    strcpy(personObj.name, "John");

    personObj.age = 30;

​

    // Access and print members of personObj

    printf("%s\n", personObj.name);

    printf("%d\n", personObj.age);

​

    return 0;

}

​

John
30

Explanation of code:

• struct Person { char name[50]; int age;};: This defines a struct name 'Person'. The 'Person' struct has two members: 'name' and 'age'.
• struct Person personObj;: This declares a variable of Person Struct named 'personObj'.
• strcpy(personObj.name, "John");: This initializes the 'personObj' member 'name' with value "John". The 'strcpy' function is used to assign the value "John" to 'personObj.name' member by copying.
• personObj.age = 30;: This initializes the 'personObj' member 'age' with value 30.
• printf("%s\n", personObj.name); and printf("%d\n", personObj.age);: These are used to access members of 'personObj' and print their vaules.
• Please note that to access a member of struct a period (.) is used between variable (object) of struct and its member.