added code for converting unix time stamp to human readable format

CodeBase/UnixTimeStampToHumanReadableFormat.cpp

@@ -0,0 +1,144 @@
+/**
+ * PROBLEM: Convert unix timestamp given in miliseconds to a human readable format
+ * AUTHOR: ashutoshshisodia
+ **/
+
+#include<bits/stdc++.h>
+
+using namespace std;
+
+bool isLeapYear(int currYear) {
+    if(currYear % 400 == 0 || (currYear % 4 == 0 && currYear % 100 != 0)) {
+        return true;
+    }
+
+    return false;
+}
+
+// seconds -> DD:MM:YYYY:HH:MM:SS, Start of unix time - 01 Jan 1970, 00:00:00
+
+string convertUnixTimeStampToHumanReadable(long int unixTime) {
+    string ans = "";
+
+    int daysOfMonth[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+    long int currYear,
+    daysTillNow,
+    extraTime,
+    extraDays,
+    index,
+    date,
+    month,
+    hours,
+    minutes,
+    seconds,
+    flag = 0;
+
+    // adding 1 because daysTillNow will give days till previous day and we have to include current day for DATE and MONTH
+    daysTillNow = (unixTime / (24 * 60 * 60)) + 1;
+
+    extraTime = unixTime  % (24 * 60 * 60);
+
+    currYear = 1970;     // year calculation will start from Epoch's year (1970)
+
+
+// calculating currrent year
+    while((daysTillNow > 365 && !isLeapYear(currYear)) || ((daysTillNow > 366 && isLeapYear(currYear)))) {
+        if(isLeapYear(currYear)) { // checking if an year is a leap year
+            daysTillNow -= 366;
+        } else {
+            daysTillNow -= 365;
+        }
+
+        currYear += 1; 
+    }
+
+// updating extradays    
+    extraDays = daysTillNow; // because daysTillNow is reduced till remaining days
+
+    if(isLeapYear(currYear)) {
+        flag = 1;
+    }
+
+// calculating MONTH and DATE
+    month = 0, index = 0; 
+    if(flag == 1) { // if it is a leap year
+        while(true) {
+            if(index == 1) {
+                if(extraDays - 29 < 0)
+                    break;
+                month += 1;
+                extraDays -= 29;    
+            } else {
+                if(extraDays - daysOfMonth[index] < 0) {
+                    break;
+                }
+
+                month += 1;
+                extraDays -= daysOfMonth[index];
+                if(extraDays <= 0) {
+                    break;
+                }
+            }
+
+            index += 1;
+        }
+    } else  {          // if this is not a leap year
+        while(true) { 
+            if(extraDays - daysOfMonth[index] < 0) {
+                break;
+            }
+
+            month += 1;
+            extraDays -= daysOfMonth[index];
+
+            if(extraDays <= 0){
+                break;
+            }
+
+            index += 1; 
+        }
+    }
+
+    if(extraDays > 0) {  // we are in (month + 1)th month.
+        month += 1;
+        date = extraDays;
+    } else {
+        if(month == 2 && flag == 1) {
+            date = 29;
+        } else {
+            date = daysOfMonth[month - 1];
+        }    
+    }
+
+// calculating Hours:Minutes:Seconds    
+
+    hours = extraTime / 3600;
+    minutes = (extraTime % 3600) / 60;
+    seconds = (extraTime % 3600) % 60;
+
+    ans += to_string(date);
+    ans += "/";
+    ans += to_string(month);
+    ans += "/";
+    ans += to_string(currYear);
+    ans += " ";
+    ans += to_string(hours);
+    ans += ":";
+    ans += to_string(minutes);
+    ans += ":";
+    ans += to_string(seconds);
+
+    return ans;
+}
+
+int main() {
+    long int seconds = 2147483647  ;
+
+    string ans = convertUnixTimeStampToHumanReadable(seconds);
+
+    cout<<ans<<"\n\n";
+    cout<<"Cool fact:\nYEAR-2038 Problem\n2147483647 -> unix time stamp will end at this time, on January 19, 2038 at 3 hours 14 minutes 7 seconds.\nBecause 2147483647  is the maximum positive value for a 32-bit signed binary integer in computing.\n";
+
+    return 0;
+}