Why you use structure in c language?

Answer 1

Structures are handy if you have a certain set of types of information that will be used repeatedly. For example, a structure called 'address' might consist of the street number, the city, the zip code, the state, and the country. You could then create several instances of this structure, maybe for several employees or something. Each instance would have its own zip code, state, country variable etc.

Answer 2

C structures allow a programmer to combine variables related to a concept into one block. For instance, if you wanted to declare variables relating to a vehicle, you could use the following:

char *vehicle_make, *vehicle_model;

int vehicle_year;

enum { color_red, color_blue, color_green, color_gold, color_silver } vehicle_color;

vehicle_make="Slodge";

vehicle_model="Guzzler";

vehicle_year=2010;

vehicle_color=color_gold;

However, sometimes you'll want to maintain multiple vehicles in memory at once. Using the above method, you'd have to employ something like the following block:

char *vehicle1_make, *vehicle1_model;

int vehicle1_year;

enum { color_red, color_blue, color_green, color_gold, color_silver } vehicle1_color;

char *vehicle2_make, *vehicle2_model;

int vehicle2_year;

enum { color_red, color_blue, color_green, color_gold, color_silver } vehicle2_color;

And so forth. This can get very messy. Instead, you can use the 'struct' declaration as follows:

enum vehicle_color { color_red, color_blue, color_green, color_gold, color_silver };

struct vehicle {

char *make, *model;

int year;

vehicle_color color;

};

struct vehicle vehicle1, vehicle2;

vehicle1.make="Slodge";

vehicle1.model="Guzzler";

vehicle1.year=2010;

vehicle1.color=color_gold;

Now that you have a struct, you can also write a function that automatically sets a vehicle's members in one statement:

void vehicle_set(struct vehicle *vehicle, char *make, char *model, int year, vehicle_color color)

{

vehicle->make=make;

vehicle->model=model;

vehicle->year=year;

vehicle->color=color;

}

vehicle_set(&vehicle1, "Slodge", "Guzzler", 2010, color_gold);

Keep in mind that if you use pointers in structures like I did above, and you begin working with files, then writing vehicle1 to a file instead of its individual members means you'll write the pointers to the variables, and not the variable data, to files.

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