Defining structs
- C course
- Beginner
- Lesson 94/116
- 5 min
Learn to define a struct that combines multiple fields.
struct: grouping data
A struct groups data of different types under one roof. It starts with the struct keyword and members go inside curly braces.
struct Point {
int x;
int y;
};Here struct Point is a type with two int members. The semicolon at the end is mandatory. This is the basic tool to manage two coordinates of a point together. The same approach can model many real objects like student, book or product.
Defining members
Struct members are written inside curly braces like normal variable declarations. Each member has its own type and name.
struct Book {
char title[64];
int year;
double price;
};Here title is a string, year is an integer, price is a double. Member names must be unique within the same struct. To access a member you use the . operator; we will see this in the next lesson.
Practice Define struct Point and print
Define struct Point with int x and int y members. In main create a Point variable with {3, 4} and print x and y with printf.
Starter code
#include <stdio.h>
/* Define struct Point with int x and int y */
int main(void) {
/* Create a Point and print it with printf */
return 0;
}Sample solution
struct Point { int x; int y; };
struct Point p = {3, 4};
printf("%d %d\n", p.x, p.y);Expected output
3 4
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which keyword is used to declare a struct?
- type
- class
- struct Correct answer
- record
Explanation: In C the struct keyword declares a struct.
2 Fill in the blank: struct definition
struct Point {
int x;
int ____;
};struct Point {
int x;
int y;
};Explanation: The second member of Point is y.
3 Match concept to explanation
| Term | Meaning |
|---|---|
struct |
Struct keyword |
member |
Variable inside struct |
{ } |
Surrounds members |
; |
Ends definition |