Arrays in C Programming

Introduction

• Welcome back to the C programming series.
• Today, we will learn about arrays in C.
• Arrays allow storing multiple data items in a single variable.

What is an Array?

• An array is a collection of similar types of data.
• Example: To store the ages of 100 people, instead of creating 100 variables, we can use a single array.

Declaring an Array in C

• Syntax for array declaration:
  data_type array_name[array_size];
  • data_type: Type of data stored (e.g., int, float).
  • array_name: Identifier for the array.
  • array_size: Number of elements the array can hold.
• Example: int age[5];
  • Declares an array of integers to store the ages of 5 people.
• Note: Size and data type cannot be changed after declaration.

Assigning Values to an Array

• Values are assigned using the equal to operator (=).
• Example: age = {21, 29, 25, 32, 17};
• If the number of elements is lesser than declared size, remaining elements default to 0.

Array Indexing

• Each element in an array is associated with an index, starting from 0.
  • Example: age[0] accesses the first element.
• Accessing elements:
  • To print elements, use:
    printf("%d", age[index]);

Individual Assignment of Values

• Values can also be assigned individually using their index:
  • Example: age[0] = 21;
• Input from the user can also be stored in arrays using scanf.

Modifying Array Elements

• Changing the value of an array element is straightforward:
  • Example: age[2] = 26;

Using Loops with Arrays

• Instead of writing multiple scanf or printf statements, we can use loops.
• Example for input:

  for (int i = 0; i < 5; i++) {
      scanf("%d", &age[i]);
  }
  

• Example for output:

  for (int i = 0; i < 5; i++) {
      printf("%d", age[i]);
  }
  

Common Mistake - Out of Bounds Access

• Be cautious about accessing array elements out of bounds. Example: If an array of size 5 is accessed with index 5, it results in unexpected behavior.

Programming Task

• Create a program to compute the average marks of a student:
  • Use an array to store marks of 5 subjects.
  • Compute total and average marks.
• Solutions available in GitHub repository.

Conclusion

• Review concepts learned in this video.
• Engage with the content: comment on the programming squeeze question.