C STRUCTURE TUTORIAL PART 1
CONTENTS
• I. INTRODUCTION
• II. VOCABULARY
• III. THE C STRUCTURE
• IV. EXAMPLE PROGRAM
• V. REFERENCES
WHAT YOU WILL LEARN IN THIS TUTORIAL
1. You will learn C structure vocabulary.
2. You will learn how to declare a structure.
3. You will learn how memory for a structure is allocated.
4. You will learn how to declare an instance of a structure.
• I. INTRODUCTION
Hello; nice to meet you. Welcome to the “C Structure Tutorial Part 1.”
C++ includes the entire C language; therefore, all C programs, with a few minor exceptions, are also C++ programs.
The C code shown in the tutorial were written using the Microsoft Visual C++ 2008 Express Edition Integrated Development Environment (IDE) and the “C99 subset.”
• II. VOCABULARY
1. What is a structure?
A structure is a collection of logically related variables of different types. A structure groups logically related standard or user defined data types. Once declared, a structure defines a template for creating compound variable type objects which are instances of a structure.
Structures can be nested as elements in other structures. Structures can be used recursively. Structures can be used to define new data types.
2. What is a tag?
A structure type name is referred to as a tag. The tag appears right after the keyword struct.
If your program uses only one structure_variable, you do not need the structure_type_name.
3. What do you call variables that make up a structure?
The variables that make up the structure are called members, elements, or fields.
• III. THE C STRUCTURE
1. How do you declare a structure?
The syntax for simultaneously declaring a structure template and creating compound variable type objects is as follows:
struct structure_type_name{ // keyword struct and tag, user defined type
type member_name; // members, elements, or fields
type member_name;
type member_name;
.
.
.
}structure_variables; // compound variable type objects
2. How do you allocate memory for a structure?
Memory is automatically allocated for all the members by the compiler when a structure variable is declared.
3. How do you define an instance of a structure?
After the structure template has been defined, an instance of a physical compound variable type object, a structure_variable can be declared using the following syntax:
struct structure_type_name structure_variable;
• IV. EXAMPLE PROGRAM
//**********************************
// C STRUCTURE TUTORIAL PART 1
//**********************************
#include<conio.h> // contains function prototypes
#include<ctype.h> // character handling
#include<stdio.h> // input/output
#include<stdlib.h> // general utilities
#include<string.h> // string handling
struct item // structure declaration
{
int item_stock_number; // member, element, or field
char *item_name; // member, element, or field
char *item_description; // member, element, or field
float item_cost; // member, element, or field
float item_sales_price; // member, element, or field
int item_inventory_quantity; // member, element, or field
}item1, item2, item3; // compound variable type objects
void f_item1(void); // function prototype
void f_item2(void); // function prototype
void f_item3(void); // function prototype
void p_item1(void); // function prototype
void p_item2(void); // function prototype
void p_item3(void); // function prototype
int main(void)
{
f_item1(); // function call
f_item2(); // function call
f_item3(); // function call
p_item1(); // function call
p_item2(); // function call
p_item3(); // function call
char ch;
ch = getch(); // keeps screen from closing until a key is pressed
return 0;
}
void f_item1(void) // function definition
{
item1.item_stock_number = 128;
item1.item_name = "Diamond Cufflinks";
item1.item_description = "Each 3 Carat Skull Shaped, 9K (375Au) yellow gold.";
item1.item_cost = 250.00;
item1.item_sales_price = 2500.00;
item1.item_inventory_quantity = 10;
}
void f_item2(void) // function definition
{
item2.item_stock_number = 142;
item2.item_name = "Ruby Cufflinks";
item2.item_description = "Each 3 Carat Skull Shapped, 9K (375Au) yellow gold.";
item2.item_cost = 500.00;
item2.item_sales_price = 5000.00;
item2.item_inventory_quantity = 20;
}
void f_item3(void) // function definition
{
item3.item_stock_number = 187;
item3.item_name = "Sapphire Cufflinks";
item3.item_description = "Each 3 Carat Skull Shapped, 9K (375Au) yellow gold.";
item3.item_cost = 1000.00;
item3.item_sales_price = 10000.00;
item3.item_inventory_quantity = 30;
}
void p_item1(void) // function definition
{
printf("Stock Number: %i \n", item1.item_stock_number);
printf("Name: %s \n", item1.item_name);
printf("Description: %s \n", item1.item_description);
printf("Cost: $%.2f \n", item1.item_cost);
printf("Sales Price: $%.2f \n", item1.item_sales_price);
printf("Inventory: %i \n\n\n", item1.item_inventory_quantity);
}
void p_item2(void) // function definition
{
printf("Stock Number: %i \n", item2.item_stock_number);
printf("Name: %s \n", item2.item_name);
printf("Description: %s \n", item2.item_description);
printf("Cost: $%.2f \n", item2.item_cost);
printf("Sales Price: $%.2f \n", item2.item_sales_price);
printf("Inventory: %i \n\n\n", item2.item_inventory_quantity);
}
void p_item3(void) // function definition
{
printf("Stock Number: %i \n", item3.item_stock_number);
printf("Name: %s \n", item3.item_name);
printf("Description: %s \n", item3.item_description);
printf("Cost: $%.2f \n", item3.item_cost);
printf("Sales Price: $%.2f \n", item3.item_sales_price);
printf("Inventory: %i \n\n\n", item3.item_inventory_quantity);
}
• V. REFERENCES
The C Programming Language by Brian Kernighan and Dennis Ritchie (Englewood Cliffs, N.J.: Prentice-Hall, 1978).
C++: The Complete Reference, Fourth Edition by Herbert Schildt (Berkeley, California: McGraw-Hill/Osborne, 2003).
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