Python vs C/Java Modulo Math: Why -1 % 5 = 4

Why -1 % 5 Is 4 in Python (But -1 in C/Java) We all learn that % means “remainder”. But here’s something interesting: In Python: -1 % 5 Result: 4 In C, C++, or Java: -1 Same math. Different answers. Why? Python thinks in circles. C/C++/Java think in straight lines. First Understand Modulo Like a Circle. Forget division for a moment. Think of numbers arranged in a circle: 0 → 1 → 2 → 3 → 4 → (back to 0) This is mod 5. It means numbers are allowed to stay only between: 0 and 4 Now ask: If you move 1 step backward from 0, where do you land? You wrap around to: 4 So mathematically: -1 mod 5 = 4 Because modulo means: “Wrap the number into the range 0 to n-1” Python’s Rule: Python follows the mathematical definition. > Result stays inside 0 to n-1 > Sign follows the divisor (positive, here 5) So: -1 % 5 = 4 -2 % 5 = 3 -6 % 5 = 4 Always wrapped into the positive range. C / C++ / Java’s Rule: These languages think differently. They:  > Keep the sign of the first number (negative, here -1) > Allow negative remainders So: -1 % 5 = -1 No wrapping. #Python #Programming #ComputerScience #ContinuousLearning

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