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Livecoding.tv Quiz of the day

September, 29 2016: PHP

5-image

Answer:

The correct answer is 18.

Here’s why:

PHP supports automatic type conversion based on the context in which a variable or value is being used.

If you perform an arithmetic operation on an expression that contains a string, that string will be interpreted as the appropriate numeric type for the purposes of evaluating the expression. So, if the string begins with one or more numeric characters, the remainder of the string (if any) will be ignored and the numeric value is interpreted as the appropriate numeric type. On the other hand, if the string begins with a non-numeric character, then it will evaluate to zero.

With that understanding, we can see that “15%” evaluates to the numeric value 15 and “$25” evaluates to the numeric value zero, which explains why the result of the statement $x = 3 + “15%” + “$25” is 18 (i.e., 3 + 15 + 0).

September, 23 2016: JavaScript

4-image

Answer:

The code above prints 5.

The trick of this question is that in the IIFE there are two assignments but the variable a is declared using the keyword var. What this means is that a is a local variable of the function. On the contrary, b is assigned to the global scope.

The other trick of this question is that it doesn’t use strict mode ( 'use strict';) inside the function. If strict mode was enabled, the code would raise the error Uncaught ReferenceError: b is not defined. Remember that strict mode requires you to explicitly reference to the global scope if this was the intended behavior. So, you should write:

 

About author

I, Dr. Michael J. Garbade is the co-founder of the Education Ecosystem (aka LiveEdu), ex-Amazon, GE, Rebate Networks, Y-combinator. Python, Django, and DevOps Engineer. Serial Entrepreneur. Experienced in raising venture funding. I speak English and German as mother tongues. I have a Masters in Business Administration and Physics, and a Ph.D. in Venture Capital Financing. Currently, I am the Project Lead on the community project -Nationalcoronalvirus Hotline I write subject matter expert technical and business articles in leading blogs like Opensource.com, Dzone.com, Cybrary, Businessinsider, Entrepreneur.com, TechinAsia, Coindesk, and Cointelegraph. I am a frequent speaker and panelist at tech and blockchain conferences around the globe. I serve as a start-up mentor at Axel Springer Accelerator, NY Edtech Accelerator, Seedstars, and Learnlaunch Accelerator. I love hackathons and often serve as a technical judge on hackathon panels.