Converting characters to integers in Java

The java.lang.Character.getNumericValue(char ch) returns the int value that the specified Unicode character represents. For example, the character ‘\u216C’ (the roman numeral fifty) will return an int with a value of 50. The letters A-Z in their uppercase (‘\u0041’ through ‘\u005A’), lowercase (‘\u0061’ through ‘\u007A’), and full width variant (‘\uFF21’ through ‘\uFF3A’ and ‘\uFF41’ through ‘\uFF5A’) forms have numeric values from 10 through 35. This is … Read more

How to track down a “double free or corruption” error

If you’re using glibc, you can set the MALLOC_CHECK_ environment variable to 2, this will cause glibc to use an error tolerant version of malloc, which will cause your program to abort at the point where the double free is done. You can set this from gdb by using the set environment MALLOC_CHECK_ 2 command before running your program; the program … Read more

How do I reference a local image in React?

First of all wrap the src in {} Then if using Webpack; Instead of: <img src={“./logo.jpeg”} /> You may need to use require: <img src={require(‘./logo.jpeg’)} /> Another option would be to first import the image as such: import logo from ‘./logo.jpeg’; // with import or … const logo = require(‘./logo.jpeg); // with require then plug it in… … Read more

Is there a way to get Bing’s photo of the day?

I think the best way is immitating the way they do it themselves through their AJAX calls. They call this URL and extract the information through XML deserialization. XML: http://www.bing.com/HPImageArchive.aspx?format=xml&idx=0&n=1&mkt=en-US JSON: http://www.bing.com/HPImageArchive.aspx?format=js&idx=0&n=1&mkt=en-US RSS: http://www.bing.com/HPImageArchive.aspx?format=rss&idx=0&n=1&mkt=en-US The mkt attribute can obviously be changed to a different region than ´en-US´, but can also be opted out of entirely if you don’t care about … Read more

What is “Advanced” SQL?

Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING Intermediate JOINs, ANSI-89 and ANSI-92 syntax UNION vs UNION ALL NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated WITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic … Read more

Read file line by line using ifstream in C++

First, make an ifstream: The two standard methods are: Assume that every line consists of two numbers and read token by token:int a, b; while (infile >> a >> b) { // process pair (a,b) } Line-based parsing, using string streams:#include <sstream> #include <string> std::string line; while (std::getline(infile, line)) { std::istringstream iss(line); int a, b; if … Read more

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