The article illustrates the working of the different relational operator on the array STL. The **equality comparison ( == )** is performed by comparing the elements sequentially using operator ( == ), stopping at the first mismatch.

The **less-than comparison ( < )** or **greater-than comparison ( > )** behaves as if using algorithm lexicographical_compare, which compares the elements sequentially using operator () in a reciprocal manner (i.e., checking both a<b and b<a) and stopping at the first occurrence.

The implementation of relational operators on the array help us to compare between the data stored in different arrays.

**Equivalent operators : **Here are some operators whose work is same.

(a != b) is equivalent to !(a == b) (a > b) equivalent to (b < a) (a <= b) equivalent to !(b < a)

**Time Complexity :** The time complexity of the above operation is **O(n)** where n is the size of the array.

Below is the code to illustrate the working of relational operators on array

**Program 1:** Relational Operator Comparison

`// array comparisons using relational operators` `#include <bits/stdc++.h>` `using` `namespace` `std;` ` ` `int` `main()` `{` ` ` `// declaration of array` ` ` `array<` `int` `, 5> a = { 1, 2, 3, 4, 5 };` ` ` `array<` `int` `, 5> b = { 1, 2, 3, 4, 5 };` ` ` `array<` `int` `, 5> c = { 5, 4, 3, 2, 1 };` ` ` ` ` `if` `(a >= b) {` ` ` `cout << ` `"a is greater than equal to b\n"` `;` ` ` `}` ` ` `else` `{` ` ` `cout << ` `"a is neither greater than nor equal to b\n"` `;` ` ` `}` ` ` ` ` `if` `(b < c) {` ` ` `cout << ` `"b is less than c\n"` `;` ` ` `}` ` ` `else` `{` ` ` `cout << ` `"b is not lesser than c\n"` `;` ` ` `}` ` ` `if` `(a >= c) {` ` ` `cout << ` `"a is greater than equal to c\n"` `;` ` ` `}` ` ` `else` `{` ` ` `cout << ` `"a is neither greater than nor equal to c\n"` `;` ` ` `}` ` ` ` ` `return` `0;` `}` |

**Output :**

a is greater than equal to b b is less than c a is neither greater than nor equal to c

**Program 2:** Relational Operator Equality

`// CPP program to check for array qualities.` `#include <bits/stdc++.h>` `using` `namespace` `std;` ` ` `int` `main()` `{` ` ` `// declaration of array` ` ` `array<` `char` `, 5> a = { ` `'a'` `, ` `'b'` `, ` `'c'` `, ` `'d'` `, ` `'e'` `};` ` ` `array<` `char` `, 5> b = { ` `'e'` `, ` `'d'` `, ` `'c'` `, ` `'b'` `, ` `'a'` `};` ` ` `array<` `char` `, 5> c = { ` `'a'` `, ` `'b'` `, ` `'c'` `, ` `'d'` `, ` `'e'` `};` ` ` ` ` `if` `(a == b) {` ` ` `cout << ` `"a is equal to b\n"` `;` ` ` `}` ` ` `else` `{` ` ` `cout << ` `"a is not equal to b\n"` `;` ` ` `}` ` ` ` ` `if` `(b != c) {` ` ` `cout << ` `"b is not equal to c\n"` `;` ` ` `}` ` ` `else` `{` ` ` `cout << ` `"b is equal to c\n"` `;` ` ` `}` ` ` `if` `(a == c) {` ` ` `cout << ` `"a is equal to c\n"` `;` ` ` `}` ` ` `else` `{` ` ` `cout << ` `"a is not equal to c\n"` `;` ` ` `}` ` ` ` ` `return` `0;` `}` |

**Output :**

a is not equal to b b is not equal to c a is equal to c

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