Initializing Structs

Part of the Logic & Flow section of Coddy's C journey — lesson 42 of 63.

While you can create struct variables and then assign values to their members individually, C provides a more convenient way to set initial values. You can initialize a struct variable at the time of declaration using an initializer list enclosed in curly braces.

The syntax for struct initialization is:

struct StructureName variableName = {value1, value2, ...};

Using our Point struct example, you can declare and initialize it in one clean line:

struct Point p1 = {10, 20};

This creates a Point variable named p1 with x set to 10 and y set to 20. The values in the initializer list are assigned to the struct members in the order they were declared in the struct definition.

This initialization approach is not only more concise than separate assignments, but it also ensures your struct starts with meaningful values rather than random garbage data. It's particularly useful when you know the initial values at compile time and want to create ready-to-use struct variables efficiently.

Challenge

Easy

Create a C program that demonstrates struct initialization using initializer lists. Your program should:

Define a struct named Employee with the following members:
- An integer id to store the employee ID
- A character array department with size 15 to store the department name
- An integer yearsOfService to store years of service
- A float salary to store the employee's salary
Create three Employee variables using initializer lists with the following data:
- emp1: ID 101, department "Engineering", 5 years of service, salary 75000.50
- emp2: ID 102, department "Marketing", 3 years of service, salary 65000.25
- emp3: ID 103, department "Sales", 8 years of service, salary 80000.75
Print the information for each employee in this exact format:
- Employee 1:
- ID: [id]
- Department: [department]
- Years of Service: [yearsOfService]
- Salary: [salary]
- Employee 2:
- ID: [id]
- Department: [department]
- Years of Service: [yearsOfService]
- Salary: [salary]
- Employee 3:
- ID: [id]
- Department: [department]
- Years of Service: [yearsOfService]
- Salary: [salary]
Calculate and print the total salary of all three employees in the format: Total Salary: [total]
Calculate and print the average years of service in the format: Average Years of Service: [average]

This challenge tests your understanding of struct initialization using initializer lists, where you declare and initialize struct variables in a single line. The values in the initializer list must be provided in the same order as the members were declared in the struct definition.

Your expected output should be:

Employee 1:
ID: 101
Department: Engineering
Years of Service: 5
Salary: 75000.50
Employee 2:
ID: 102
Department: Marketing
Years of Service: 3
Salary: 65000.25
Employee 3:
ID: 103
Department: Sales
Years of Service: 8
Salary: 80000.75
Total Salary: 220001.50
Average Years of Service: 5.33

Cheat sheet

You can initialize a struct variable at declaration time using an initializer list enclosed in curly braces:

struct StructureName variableName = {value1, value2, ...};

Example with a Point struct:

struct Point p1 = {10, 20};

The values in the initializer list are assigned to struct members in the order they were declared in the struct definition. This approach is more concise than separate assignments and ensures your struct starts with meaningful values rather than random garbage data.

Try it yourself

#include <stdio.h>

// TODO: Define the Employee struct here

int main() {
    // TODO: Create three Employee variables using initializer lists
    
    // TODO: Print information for each employee
    
    // TODO: Calculate and print total salary and average years of service
    
    return 0;
}