Difference between Array and Union in C

1. Array in C : 
An array is collection of similar data items accessed by a common name stored at continuous memory locations. The elements of an array can be accessed using indices. They can be used to store primitive data types such as int, float, double, char, etc. but all elements have to be of the same data type. Below is the picturesque representation of an array. 

 

Declaration of an array : 
 

datatype array_name[size]

2. Union in C : 
Union is a user defined datatype that allows storage of heterogeneous elements in the same memory location. Size of the union is the size of the largest element in the union. Below is the picturesque representation of a union. 

 

Declaration of a union : 
 

union name
{
  datatype element;
  datatype element;
};

Difference between Array and Union :