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CS50 Quiz 1

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CS50 Quiz 1

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1. JavaScript

Forbiddenis a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

2. gdb vs. valgrind

is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.ForbiddenYou should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

3. GET vs. POST

You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.Forbidden

4. HTTP Status Code 403:

ForbiddenYou should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

5. Hash table vs. trie

You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.A hash table should be used when you have a sparse data set (e.g., words that tend not to share long common prefixes), as a trie's nodes (each of which contains an array) would likely take up much more spaceYou should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.is a client-side programming language supported by today's browsers.

6. MySQL vs. CSV

is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.MySQL should be used when you have a lot of data that you'd like to be able to search efficiently. MySQL can build indexes for fields that expedite searches. CSV files must be searched linearly.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

7. Associative array

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.an array whose indices can't only be integers but strings & other types as well. Put another way, it is an object w/key-value pairs.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.

8. HTTP Status Code 200:

9. Octal notation

(otherwise known as base-8) is a base system w/8 digits: 0 through 7. It happens to be used by chmod for permissionsYou should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.

10. 5 states of AJAX request:

0: not initialized 1: connection established 2: request received 3: answer in progress 4: doneis a client-side programming language supported by today's browsers.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.

11. Anonymous function

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.otherwise known as a lambda function, is a function w/out a name. Popular in JavaScript, anonymous functions can be passed as inputs to functions so as to be called lateris a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.

12. HTTP Status Code 301:

You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.Moved PermanentlyYou should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

13. Ajax

is a programming technique that couples JavaScript with XML (or JSON) in such a way that browsers can request additional data from servers via HTTP even after an initial page load is complete.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.

14. HTTP Status Code 401:

UNAUTHORIZED. INTRUDER ALERT.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.

15. JSON vs. CSV

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.JSON should be used when you'd like to associate non-numeric keys w/values, so that you needn't worry about fields' relative ordering. JSON should also be used when you'd like to represent hierarchical structures. A CSV file, by contrast, doesn't allow for hierarchy & you must know a priori which fields are in which columns (unless the CSV file's header row contains fields' names).is a client-side programming language supported by today's browsers.

16. Passing by reference vs. passing by value

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.You should pass an argument by reference when you want the callee to be able to change it or when the argument is a multi-byte struct that you'd like to avoid copying (which takes time & space). You should pass an argument by value when you don't want the callee to be able to change it or when the time & space involved in copying it is negligible.

17. 1-way hash

is a fixed-length string outputted by a function that takes variable-length strings as input. It is easy to compute the former given the latter, but it is computationally expensive to compute the latter given the former. If 1-way hashes of users' PWs are stored in a website's DB, the website can compute a 1-way has of the PW the same way as it did before storing it in the DB & then compare the 2 hashes. If they match the website concludes that the user entered the right PW.is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

18. Valgrind error: 40 bytes in 1 blocks are definitely lost in record 1 of 1. What is reason for error?

You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.Person has likely allocated 40 bytes of memory (as by allocating 10 ints) but failed to free them.is a client-side programming language supported by today's browsers.

19. $_COOKIE array

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.holds the values of cookies stored on the client side.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.

20. C vs. PHP

C tends to be best for high-performance apps (b/c it's compiled), PHP tends to be better for web programming (b/c it was designed with browsers in mind) & command-line scripting (b/c it comes w/richer set of functions).You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.is a client-side programming language supported by today's browsers.

21. JavaScript vs. PHP

You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.PHP is well-suited for server-side generation of HTML & DB queries; JS allows websites to interact w/users client-side (mouseover). Both JavaScript & PHP are interpreted languagesYou should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.is a client-side programming language supported by today's browsers.

22. $_SESSION array

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.holds server-side data. It helps to maintain the illusion of a continuing user session, despite the fact that HTTP is a stateless protocol.is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.

23. Local variable vs. Global variable

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.local should be used whenever possible so as to restrict variables' scope tightly so that they're only accessible where needed; global might be justified when its usage simplifies code by eliminating need to pass some local variables around to multiple functions.is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.

24. What is the difference between NULL and '\0'?

You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.is a client-side programming language supported by today's browsers.You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.NULL is a special pointer that points to no object, whereas '\0' is a char that generally demarks the end of a string.

25. Valgrind error: Invalid write of size 4. What is reason for error?

You should use gdb when you want to debug code, as by setting breakpoints, stepping through statements, & examining memory. You should use valgrind when you want to chase down memory leaks & invalid pointer dereferences.is a client-side programming language supported by today's browsers.Person has likely written to a 4-byte location in memory that does not belong to his program, as by indexing beyond the boundary of an array of ints.You should use POST when a form needs to submit more data than would reasonably fit in a URL or when a form's data warrants privacy (as do PWs). You should use GET when you want a web page & its state to be bookmarkable or emailable.

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25 Questions

❤ If you liked Fatskills, consider supporting us by checking out The Life Manuals You Never Got.

About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | OSHA Basics Quiz | What Should We Know? Privacy | Terms |

Without work one finishes nothing. - Ralph Waldo Emerson© 2026 Fatskills.com

All trademarks, logos and brand names are the property of their respective owners. All company, product and service names used in this website are for identification purposes only. Use of these names, trademarks and brands does not imply endorsement.

About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | OSHA Basics Quiz | What Should We Know?
Privacy | Terms |

Without work one finishes nothing. - Ralph Waldo Emerson
© 2026 Fatskills.com