Arrays in Computer Programming

One-Dimensional 

A one-dimensional array contains a single row of elements. It is generally indexed from 0 to n-1, where ‘n’ is the size of the array. Each element in an array can be accessed easily by using the index number assigned to it. 

The syntax of a one-dimensional array in C programming language is as follows: 

dataType arrayName[arraySize];

Example of a simple one-dimensional array in C: 

Input

#include <stdio.h> 
int main() { 
int numbers[5] = {10, 20, 30, 40, 50}; 
for(int i=0; i<5; i++) { 
printf("numbers[%d] = %d\n", i, numbers[i]); 
} 
return 0; 
}

Output

numbers[0] = 10 
numbers[1] = 20 
numbers[2] = 30 
numbers[3] = 40 
numbers[4] = 50 

Two-Dimensional 

Two-dimensional arrays are also known as matrix arrays, and they contain arrays of elements. Think of them as a grid that lays out the elements into rows and columns. You can access each element within the two-dimensional array individually by its row and column location. Two-dimensional arrays are used for storing data where each element may have multiple associated values, for example, tables or pictures.  

The syntax to declare a 2D Array in C programming language is as follows: 

data_type array_name[row_size][column_size]; 

Example of a two-dimensional array in C 

Input

#include<stdio.h> 
int main(){ 
int i=0,j=0; 
int arr[4][3]={{1,2,3},{2,3,4},{3,4,5},{4,5,6}}; 
//traversing 2D array 
for(i=0;i<4;i++){ 
for(j=0;j<3;j++){ 
printf("arr[%d] [%d] = %d \n",i,j,arr[i][j]); 
}//end of j 
}//end of i 
return 0; 
}

Output

arr[0][0] = 1 
arr[0][1] = 2 
arr[0][2] = 3 
arr[1][0] = 2 
arr[1][1] = 3 
arr[1][2] = 4 
arr[2][0] = 3 
arr[2][1] = 4 
arr[2][2] = 5 
arr[3][0] = 4 
arr[3][1] = 5 
arr[3][2] = 6 

Multi-Dimensional  

Multi-Dimensional arrays, also referred to as N-dimensional arrays, contain more than one array arranged hierarchically. They are used to store and manage data organizationally. Multi-dimensional arrays can have many dimensions. Rows and columns are the most common, although three or more dimensions can also be used. 

Here is the syntax for a multi-dimensional array in C: 

data_type array_name[size1][size2]....[sizeN]; 

Here is an example of using multi-dimensional arrays in C, where the program stores the grades of 5 students in 4 different subjects.

Input

#include <stdio.h> 
int main() { 
int grades[5][4]; 
// Prompt user to enter grades 
for (int i = 0; i< 5; i++) { 
printf("Enter grades for student %d:\n", i+1); 
for (int j = 0; j < 4; j++) { 
printf("Subject %d: ", j+1); 
scanf("%d", &grades[i][j]); 
} 
} 
// Calculate average grade for each student 
printf("\nAverage grade for each student:\n"); 
for (int i = 0; i< 5; i++) { 
float sum = 0; 
for (int j = 0; j < 4; j++) { 
sum += grades[i][j]; 
} 
float avg = sum / 4; 
printf("Student %d: %.2f\n", i+1, avg); 
} 
// Calculate average grade for each subject 
printf("\nAverage grade for each subject:\n"); 
for (int j = 0; j < 4; j++) { 
float sum = 0; 
for (int i = 0; i< 5; i++) { 
sum += grades[i][j]; 
} 
float avg = sum / 5; 
printf("Subject %d: %.2f\n", j+1, avg); 
} 
return 0; 
}

Output

Enter grades for student 1: 
Subject 1: 80 
Subject 2: 75 
Subject 3: 90 
Subject 4: 85 
Enter grades for student 2: 
Subject 1: 70 
Subject 2: 85 
Subject 3: 80 
Subject 4: 75 
Enter grades for student 3: 
Subject 1: 90 
Subject 2: 80 
Subject 3: 85 
Subject 4: 95 
Enter grades for student 4: 
Subject 1: 75 
Subject 2: 90 
Subject 3: 75 
Subject 4: 80 
Enter grades for student 5: 
Subject 1: 85 
Subject 2: 70 
Subject 3: 80 
Subject 4: 90 
Average grade for each student: 
Student 1: 82.50 
Student 2: 77.50 
Student 3: 87.50 
Student 4: 80.00 
Student 5: 81.25 
Average grade for each subject: 
Subject 1: 80.00 
Subject 2: 80.00 
Subject 3: 82.00 
Subject 4: 85.00