This problem is known as Clock angle problem where we need to find angle between hands of an analog clock at a given time.
Examples:
Input: h = 12:00 m = 30.00 Output: 165 degree Input: h = 3.00 m = 30.00 Output: 75 degree
The idea is to take 12:00 (h = 12, m = 0) as a reference. Following are detailed steps.
1. Calculate the angle made by hour hand with respect to 12:00 in h hours and m minutes.
2. Calculate the angle made by minute hand with respect to 12:00 in h hours and m minutes.
3. The difference between the two angles is the angle between the two hands.
How to calculate the two angles with respect to 12:00?
The minute hand moves 360 degrees in 60 minute(or 6 degrees in one minute) and hour hand moves 360 degrees in 12 hours(or 0.5 degrees in 1 minute). In h hours and m minutes, the minute hand would move (h*60 + m)*6 and hour hand would move (h*60 + m)*0.5.
C++
// C++ program to find angle between hour and minute hands #include <bits/stdc++.h>using namespace std;// Utility function to find minimum of two integers int min(int x, int y) { return (x < y)? x: y; } int calcAngle(double h, double m) { // validate the input if (h <0 || m < 0 || h >12 || m > 60) printf("Wrong input"); if (h == 12) h = 0; if (m == 60) { m = 0; h += 1; if(h>12) h = h-12; } // Calculate the angles moved // by hour and minute hands // with reference to 12:00 float hour_angle = 0.5 * (h * 60 + m); float minute_angle = 6 * m; // Find the difference between two angles float angle = abs(hour_angle - minute_angle); // Return the smaller angle of two possible angles angle = min(360 - angle, angle); return angle; } // Driver Code int main() { cout << calcAngle(9, 60) << endl; cout << calcAngle(3, 30) << endl; return 0; } // This is code is contributed by rathbhupendra |
C
// C program to find angle between hour and minute hands#include <stdio.h>#include <stdlib.h>// Utility function to find minimum of two integersint min(int x, int y) { return (x < y)? x: y; }int calcAngle(double h, double m){ // validate the input if (h <0 || m < 0 || h >12 || m > 60) printf("Wrong input"); if (h == 12) h = 0; if (m == 60) { m = 0; h += 1; if(h>12) h = h-12; } // Calculate the angles moved by hour and minute hands // with reference to 12:00 int hour_angle = 0.5 * (h*60 + m); int minute_angle = 6*m; // Find the difference between two angles int angle = abs(hour_angle - minute_angle); // Return the smaller angle of two possible angles angle = min(360-angle, angle); return angle;}// Driver Codeint main(){ printf("%d n", calcAngle(9, 60)); printf("%d n", calcAngle(3, 30)); return 0;} |
Java
// Java program to find angle between hour and minute handsimport java.io.*;class GFG { // Function to calculate the angle static int calcAngle(double h, double m) { // validate the input if (h <0 || m < 0 || h >12 || m > 60) System.out.println("Wrong input"); if (h == 12) h = 0; if (m == 60) { m = 0; h += 1; if(h>12) h = h-12; } // Calculate the angles moved by hour and minute hands // with reference to 12:00 int hour_angle = (int)(0.5 * (h*60 + m)); int minute_angle = (int)(6*m); // Find the difference between two angles int angle = Math.abs(hour_angle - minute_angle); // smaller angle of two possible angles angle = Math.min(360-angle, angle); return angle; } // Driver Code public static void main (String[] args) { System.out.println(calcAngle(9, 60)+" degree"); System.out.println(calcAngle(3, 30)+" degree"); }}// Contributed by Pramod Kumar |
Python3
# Python program to find angle # between hour and minute hands# Function to Calculate angle b/w # hour hand and minute hand def calcAngle(h,m): # validate the input if (h < 0 or m < 0 or h > 12 or m > 60): print('Wrong input') if (h == 12): h = 0 if (m == 60): m = 0 h += 1; if(h>12): h = h-12; # Calculate the angles moved by # hour and minute hands with # reference to 12:00 hour_angle = 0.5 * (h * 60 + m) minute_angle = 6 * m # Find the difference between two angles angle = abs(hour_angle - minute_angle) # Return the smaller angle of two # possible angles angle = min(360 - angle, angle) return angle# Driver Code h = 9m = 60print('Angle ', calcAngle(h,m))# This code is contributed by Danish Raza |
C#
// C# program to find angle between// hour and minute handsusing System;class GFG { // Function to calculate the angle static int calcAngle(double h, double m) { // validate the input if (h < 0 || m < 0 || h > 12 || m > 60) Console.Write("Wrong input"); if (h == 12) h = 0; if (m == 60) { m = 0; h += 1; if(h>12) h = h-12; } // Calculate the angles moved by hour and // minute hands with reference to 12:00 int hour_angle = (int)(0.5 * (h * 60 + m)); int minute_angle = (int)(6 * m); // Find the difference between two angles int angle = Math.Abs(hour_angle - minute_angle); // smaller angle of two possible angles angle = Math.Min(360 - angle, angle); return angle; } // Driver code public static void Main () { Console.WriteLine(calcAngle(9, 60)); Console.Write(calcAngle(3, 30)); }}// This code is contributed by Nitin Mittal. |
PHP
<?php// PHP program to find // angle between hour // and minute hands// Utility function to // find minimum of two // integersfunction mintwo($x, $y){ return ($x < $y) ? $x : $y; }function calcAngle($h, $m){ // validate the input if ($h <0 || $m < 0 || $h >12 || $m > 60) echo "Wrong input"; if ($h == 12) $h = 0; if ($m == 60) { $m = 0; $h += 1; if($h>12) $h = $h-12; } // Calculate the angles // moved by hour and // minute hands with // reference to 12:00 $hour_angle = 0.5 * ($h * 60 + $m); $minute_angle = 6 * $m; // Find the difference // between two angles $angle = abs($hour_angle - $minute_angle); // Return the smaller angle // of two possible angles $angle = min(360 - $angle, $angle); return $angle;}// Driver Codeecho calcAngle(9, 60), "\n";echo calcAngle(3, 30), "\n";// This code is contributed by ajit?> |
Javascript
<script>// Javascript program to find angle between hour and minute hands // Utility function to find minimum of two integers function min(x, y) { return (x < y)? x: y; } function calcAngle(h, m) { // validate the input if (h <0 || m < 0 || h >12 || m > 60) document.write("Wrong input"); if (h == 12) h = 0; if (m == 60) { m = 0; h += 1; if(h>12) h = h-12; } // Calculate the angles moved // by hour and minute hands // with reference to 12:00 let hour_angle = 0.5 * (h * 60 + m); let minute_angle = 6 * m; // Find the difference between two angles let angle = Math.abs(hour_angle - minute_angle); // Return the smaller angle of two possible angles angle = min(360 - angle, angle); return angle; } // Driver Code document.write(calcAngle(9, 60) + "<br>"); document.write(calcAngle(3, 30) + "<br>"); // This code is contributed by Surbhi Tyagi.</script> |
Output
60 75
Time Complexity: O(1)
Auxiliary Space: O(1)
Exercise: Find all times when hour and minute hands get superimposed.
This article is contributed by Ashish Bansal. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above
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