Given lower left and upper right coordinates **(x1, y1) and (x2, y2)** of a square, the task is to count the number of integral coordinates that lies strictly inside the square.

**Examples:**

Input:x1 = 1, y1 = 1, x2 = 5, x3 = 5

Output:9

Explanation:

Below is the square for the given coordinates:

Input:x1 = 1, y1 = 1, x2 = 4, x3 = 4

Output:4

**Approach:** The difference between the x and y ordinates of the lower and upper right coordinates of the given squares gives the number integral points of x ordinates and y ordinates between opposite sides of square respectively. The total number of points that strictly lies inside the square is given by:

count = (x2 – x1 – 1) * (y2 – y1 – 1)

**For Example:**

In the above figure:

1. The total number of integral points inside base of the square is(x2 – x1 – 1).

2. The total number of integral points inside height of the square is(y2 – y1 – 1).

These(x2 – x1 – 1)integrals points parallel to the base of the square repeats(y2 – y1 – 1)number of times. Therefore the total number of integral points is given by(x2 – x1 – 1)*(y2 – y1 – 1).

Below is the implementation of the above approach:

## C++

`// C++ program for the above approach ` `#include <bits/stdc++.h> ` `using` `namespace` `std; ` ` ` `// Function to calculate the integral ` `// points inside a square ` `void` `countIntgralPoints(` `int` `x1, ` `int` `y1, ` ` ` `int` `x2, ` `int` `y2) ` `{ ` ` ` `cout << (y2 - y1 - 1) * (x2 - x1 - 1); ` `} ` ` ` `// Driver Code ` `int` `main() ` `{ ` ` ` `int` `x1 = 1, y1 = 1; ` ` ` `int` `x2 = 4, y2 = 4; ` ` ` ` ` `countIntgralPoints(x1, y1, x2, y2); ` ` ` `return` `0; ` `} ` |

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## Java

`// Java program for the above approach ` ` ` `class` `GFG { ` ` ` `// Function to calculate the integral ` `// points inside a square ` `static` `void` `countIntgralPoints(` `int` `x1, ` `int` `y1, ` ` ` `int` `x2, ` `int` `y2) ` `{ ` ` ` `System.out.println((y2 - y1 - ` `1` `) * ` ` ` `(x2 - x1 - ` `1` `)); ` `} ` ` ` `// Driver Code ` `public` `static` `void` `main(String args[]) ` `{ ` ` ` `int` `x1 = ` `1` `, y1 = ` `1` `; ` ` ` `int` `x2 = ` `4` `, y2 = ` `4` `; ` ` ` ` ` `countIntgralPoints(x1, y1, x2, y2); ` `} ` `} ` ` ` `// This code is contributed by rutvik_56 ` |

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## Python3

`# Python3 program for the above approach ` ` ` `# Function to calculate the integral ` `# points inside a square ` `def` `countIntgralPoints(x1, y1, x2, y2): ` ` ` `print` `((y2 ` `-` `y1 ` `-` `1` `) ` `*` `(x2 ` `-` `x1 ` `-` `1` `)) ` ` ` `# Driver Code ` `if` `__name__ ` `=` `=` `'__main__'` `: ` ` ` ` ` `x1 ` `=` `1` ` ` `y1 ` `=` `1` ` ` `x2 ` `=` `4` ` ` `y2 ` `=` `4` ` ` ` ` `countIntgralPoints(x1, y1, x2, y2) ` ` ` `# This code is contributed by Samarth ` |

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## C#

`// C# program for the above approach ` `using` `System; ` ` ` `class` `GFG{ ` ` ` `// Function to calculate the integral ` `// points inside a square ` `static` `void` `countIntgralPoints(` `int` `x1, ` `int` `y1, ` ` ` `int` `x2, ` `int` `y2) ` `{ ` ` ` `Console.WriteLine((y2 - y1 - 1) * ` ` ` `(x2 - x1 - 1)); ` `} ` ` ` `// Driver code ` `static` `void` `Main() ` `{ ` ` ` `int` `x1 = 1, y1 = 1; ` ` ` `int` `x2 = 4, y2 = 4; ` ` ` ` ` `countIntgralPoints(x1, y1, x2, y2); ` `} ` `} ` ` ` `// This code is contributed by divyeshrabadiya07 ` |

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**Output:**

4

**Time Complexity:** O(1)

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