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Introduction to Arrays in C

An array in C is a collection of elements of the same data type stored in contiguous memory locations. Arrays allow you to store and manage large amounts of data efficiently.

Key Topics

1. Declaring Arrays

The syntax for declaring an array is:

data_type array_name[array_size];

Example: Declaring an Integer Array

int numbers[5];

2. Accessing Array Elements

Array elements are accessed using indices, starting from 0.

Example: Accessing Elements

numbers[0] = 10;
int value = numbers[0];

3. Initializing Arrays

Arrays can be initialized at the time of declaration.

Example: Initializing an Array

int numbers[5] = {1, 2, 3, 4, 5};

4. Arrays of Different Data Types

Arrays can be of any data type, including char, float, and double.

Example: Character Array (String)

char name[6] = {'A', 'l', 'i', 'c', 'e', '\0'};
printf("Name: %s\n", name);

Output:

Name: Alice

Example: Float Array

float temperatures[3] = {36.5, 37.0, 36.8};
for (int i = 0; i < 3; i++) {
    printf("Temperature %d: %.1f\n", i + 1, temperatures[i]);
}

Output:

Temperature 1: 36.5
Temperature 2: 37.0
Temperature 3: 36.8

Example: Double Array

double distances[4] = {5.5, 10.75, 15.0, 20.25};
for (int i = 0; i < 4; i++) {
    printf("Distance %d: %.2lf km\n", i + 1, distances[i]);
}

Output:

Distance 1: 5.50 km
Distance 2: 10.75 km
Distance 3: 15.00 km
Distance 4: 20.25 km

Example: Boolean Array

#include <stdbool.h>
bool flags[3] = {true, false, true};
for (int i = 0; i < 3; i++) {
    printf("Flag %d: %s\n", i + 1, flags[i] ? "true" : "false");
}

Output:

Flag 1: true
Flag 2: false
Flag 3: true

Best Practices

  • Always ensure array indices are within bounds to prevent undefined behavior.
  • Initialize arrays to avoid garbage values.
  • Use meaningful names for arrays to reflect their purpose.
  • Choose the appropriate data type for the array elements.

Don'ts

  • Don't access array elements outside of their defined range.
  • Don't neglect to initialize arrays if their values are used before assignment.
  • Don't mix data types within the same array; all elements must be of the same type.
  • Don't use uninitialized arrays; always assign values before use.

Key Takeaways

  • Arrays store multiple elements of the same type in contiguous memory locations.
  • Array indices start at 0 and go up to size - 1.
  • Arrays can be of any data type, such as int, char, float, or double.
  • Proper declaration, initialization, and usage are essential for correct array manipulation.
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