C Multidimensional Arrays

by CodeCapsule

1. What is a Multidimensional Array?

A multidimensional array is an array of arrays.
The most common is a 2D array, which can be thought of as a table with rows and columns.

Syntax for 2D Array:

rows → number of rows
columns → number of columns

2. Declaring and Initializing a 2D Array

Declaration Only

Declaration with Initialization

Can also initialize in a single line:

3. Accessing Elements in a 2D Array

Use row and column indices (both start from 0):

#include <stdio.h>

int main() {
int matrix[2][3] = {
{10, 20, 30},
{40, 50, 60}
};

printf("Element at row 1, column 2: %d\n", matrix[0][1]); // 20
printf("Element at row 2, column 3: %d\n", matrix[1][2]); // 60

return 0;
}

#include <stdio.h>

int main() {

int matrix[2][3] = {

{10, 20, 30},

{40, 50, 60}

};

printf("Element at row 1, column 2: %d\n", matrix[0][1]); // 20

printf("Element at row 2, column 3: %d\n", matrix[1][2]); // 60

return 0;

}

Output:

4. Looping Through a 2D Array

#include <stdio.h>

int main() {
int matrix[2][3] = {
{1, 2, 3},
{4, 5, 6}
};

for (int i = 0; i < 2; i++) { // row loop
for (int j = 0; j < 3; j++) { // column loop
printf("%d ", matrix[i][j]);
}
printf("\n");
}

return 0;
}

#include <stdio.h>

int main() {

int matrix[2][3] = {

{1, 2, 3},

{4, 5, 6}

};

for (int i = 0; i < 2; i++) { // row loop

for (int j = 0; j < 3; j++) { // column loop

printf("%d ", matrix[i][j]);

}

printf("\n");

}

return 0;

}

Output:

5. Sum of All Elements in 2D Array

#include <stdio.h>

int main() {
int matrix[2][3] = {{1, 2, 3}, {4, 5, 6}};
int sum = 0;

for (int i = 0; i < 2; i++) {
for (int j = 0; j < 3; j++) {
sum += matrix[i][j];
}
}

printf("Sum of all elements: %d\n", sum);
return 0;
}

#include <stdio.h>

int main() {

int matrix[2][3] = {{1, 2, 3}, {4, 5, 6}};

int sum = 0;

for (int i = 0; i < 2; i++) {

for (int j = 0; j < 3; j++) {

sum += matrix[i][j];

}

printf("Sum of all elements: %d\n", sum);

return 0;

}

Output:

6. Real-Life Example: Student Marks Table

#include <stdio.h>

int main() {
int marks[3][3] = {
{85, 90, 78}, // Student 1
{88, 76, 92}, // Student 2
{90, 85, 88} // Student 3
};

for (int i = 0; i < 3; i++) {
printf("Student %d marks: ", i + 1);
for (int j = 0; j < 3; j++) {
printf("%d ", marks[i][j]);
}
printf("\n");
}

return 0;
}

#include <stdio.h>

int main() {

int marks[3][3] = {

{85, 90, 78}, // Student 1

{88, 76, 92}, // Student 2

{90, 85, 88} // Student 3

};

for (int i = 0; i < 3; i++) {

printf("Student %d marks: ", i + 1);

for (int j = 0; j < 3; j++) {

printf("%d ", marks[i][j]);

}

printf("\n");

}

return 0;

}

Output:

Real-life use: Class marks, Excel-like tables, seating arrangements.

7. Key Points About Multidimensional Arrays

2D arrays = rows × columns; 3D arrays = tables of matrices.
Use nested loops to access all elements.
Memory is contiguous, so indexing is efficient.
Can initialize row-wise or single line.
Avoid accessing indices outside the declared size → undefined behavior.

C Multidimensional Arrays

1. What is a Multidimensional Array?

2. Declaring and Initializing a 2D Array

Declaration Only

Declaration with Initialization

3. Accessing Elements in a 2D Array

4. Looping Through a 2D Array

5. Sum of All Elements in 2D Array

6. Real-Life Example: Student Marks Table

7. Key Points About Multidimensional Arrays

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C Multidimensional Arrays

1. What is a Multidimensional Array?

2. Declaring and Initializing a 2D Array

Declaration Only

Declaration with Initialization

3. Accessing Elements in a 2D Array

4. Looping Through a 2D Array

5. Sum of All Elements in 2D Array

6. Real-Life Example: Student Marks Table

7. Key Points About Multidimensional Arrays

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