Today's Question:  What does your personal desk look like?        GIVE A SHOUT

SEARCH KEYWORD -- Method

  Be careful about printing error as string in GoLang

In GoLang, we can format and produce string using fmt.Printf(), just like C, GoLang also supports format verbs like %s, %d which can be placeholder for different types of values. But please pay attention when printing error as string so that you will not fall into some trap. Let's first take an example code snippet and see what trap we are talking about. package main import "fmt" type A string func (a A) Error() string { return fmt.Sprintf("%s is an error", a) } func main() { a := A("hello...

   STACKOVERFLOW,GOLANG,FMT     2019-01-23 09:17:15

  Java AbstractMethodError explained and demonstrated

According to Oracle Java API documentation, AbstractMethodError is a kind of runtime error where the application is having some incompatible changes which leads to a missing implementation of an abstract method. Below is the official description. Thrown when an application tries to call an abstract method. Normally, this error is caught by the compiler; this error can only occur at run time if the definition of some class has incompatibly changed since the currently executing method was last co...

   JAVA,ABSTRACTMETHODERROR     2016-07-22 22:03:20

  How to check whether a struct implements an interface in GoLang

Unlike other programming languages like Java, when implementing an interface in GoLang, there is no syntax like below to explicit tell the relationship: type I interface { } type A struct implements I { } When looking at the code or running the code in GoLang, it might lead to a case one doesn't know whether a struct implements interface before trying to use it as some interface. According to GoLang spec, as long as a struct implements all functions of an interface, it is considered as having i...

   GOLANG,INTERFACE,IMPLEMENTATION,CHECK     2020-05-03 00:05:54

  Traditional recursion vs Tail recursion

Recursion is a frequently adopted pattern for solving some sort of algorithm problems which need to divide and conquer a big issue and solve the smaller but the same issue first. For example, calculating fibonacci  accumulating sum and calculating factorials. In these kinds of issues, recursion is more straightforward than their loop counterpart. Furthermore, recursion may need less code and looks more concise. For example, let's calculate sum of a set of numbers starting with 0 and st...

   ALGORITHM,RECURSION,TAIL RECURSION,TRADITIONAL RECURSION     2016-09-23 23:54:09

  A return to good code

Stop doing this:public boolean foo() { if (true) {   return true;   }  else {   return false;   }}It always amazes me when I dig into an open source project, and I see code written by supposed experts, and reviewed by seasoned professionals, and nobody slaps the wrists of the developer who shoves return statements right in the middle of a method.Tell me, how hard is it to do this:public boolean foo() {   boolean flag = true;  ...

   Java,Code,Method,Return,Condition     2011-03-23 01:24:47

  3 meanings of Stack

We may frequently see stack when we read programming books. But many times we may be confused about the different meanings of it. This term actually has three common meanings. Here we explain the three different meanings of Stack in programming. 1. Data structure The first meaning of Stack defines a method for storing data. Its feature is LIFO9Last In First Out). In this data structure, data are accumulated level by level. The data last put in is added at the top of the stack. When using the dat...

   Stack,Memory,Data structure     2014-02-24 04:56:46

  Read white space with scanf()

Usually, when we want to enter string with white spaces in C, we need to call gets() or fgets(0 method. We usually will not use scanf(0 or fscanf() because they cannot accept white spaces when scan user inputs.   But when we specify the format in scanf() function, we may read strings with white space. the code section below illustrate this: #include <stdio.h>   int main(int argc,char **argv){        char name[30];      fprintf(stdout,"Please en...

   C,scanf,white space, string format     2011-09-26 11:45:43

  Scala, Patterns and The Perl Effect

He tried to understand that one concept for a couple of months before it made sense to him. Admittedly, partial functions are not intuitive for anyone who has been schooled in traditional programming, but still, looking at the problem he was trying to solve it seemed like James was required to expend too much effort relative to the simplicity of the problem (as he pointed out, now that he understands the concept it seems straightforward). He showed me the code, and it was basically a situa...

   Scala,Perl,Pattern,Partial function,Template     2011-12-21 09:25:41

  trim() in JavaScript

In the past, JavaScript didn't define the trim() function for String object. This makes web programmers frustrated since they often need to implement this function themselves if they want to handle user inputs. The new version of ECMA-262 introduces the trim() function.15.5.4.20   String.prototype.trim ( )     The following steps are taken:     1.   Call CheckObjectCoercible passing the this value as its argument.   2.   Let S...

   JavaScript,trim(),implementation     2012-07-19 10:58:01

  String intern in Java

In Java, == is used to compare whether two objects have the same memory location, equals() is usually used to compare whether two objects have the same time and the same state.  When comparing two strings, normally we just want to know whether they have same content, so we can choose equals(). But since String comparison is so frequently needed, Java has worked on the String class to make == workable when comparing two String literals. The String class maintains a pool of emp...

   JAVA,STRING     2016-04-10 03:35:25

RECENT