![\"Box](\"https:\/\/www.mcdonalds.com\/is\/image\/content\/dam\/uk\/nfl\/nutrition\/nfl-product\/product\/products\/mcdonalds-20-Chicken-McNuggets-ShareBox.jpg\")
\nChicken McNuggets come several to a box, depending on what you order: six pieces for a kid, nine pieces for an adult, or twenty pieces for an honest adult. These numbers in various combinations form what the math nerds call McNugget Numbers.
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\nYes, leave it up to the math nerds to take something delightful and turn it into a number game. Or, in this case, a programming puzzle.<\/p>\n
The way this puzzle works is that any value evenly divisible by a McNuggets quantity (6, 9, 20) is a McNuggets number. Right away, 6, 9, and 20 are McNuggets numbers. But so are 12 (6+6) and 15 (6+9) and 44 (20+6+6+6+6). Any value that isn’t a combination of 6, 9, and\/or 20 is a non-McNuggets number.<\/p>\n
Using the Power Of The Computer, it’s possible to determine which values are McNuggets numbers and which aren’t. Specifically, the programming puzzle presented on Rosetta Code<\/a> is to identify the highest non-McNuggets number less than 100.<\/p>\n This problem should be attractive to programmers who love to practice their coding kung fu. I thought it might make an interesting Exercise for this blog. But then I looked at the C language solution provided on Rosetta Code, which is shown below. Keep in mind that this isn’t my code:<\/p>\n Immediately my eyeballs are assaulted by the abundance of heathen goto<\/em> statements in the sacred C code. My first impression upon seeing this C language solution was to wonder whether this is the super rare and perhaps only legitimate example of where goto<\/em> must be used to solve a programming puzzle. I mean, what self-respecting C coder would boldly submit such code for the public to witness? Obviously something is going on here.<\/p>\n The output generates the proper value, so functionally the code is fine:<\/p>\n The goto<\/em> keyword aside, the code cleverly uses nested loops to plow through values Globally replacing the goto<\/em> statements with a continue<\/em> statement doesn’t work. I didn’t think it would, but I had to try. After all, continue<\/em> is another way to keep a loop going while skipping over the rest of the loop’s statements.<\/p>\n I’m convinced that the approach shown in this code has merit. But can the code be re-written to avoid using goto<\/em>? If it can’t, this example provides one legitimate puzzle that requires goto<\/em> in the C language. I just don’t believe it’s true!<\/p>\n If you can re-write this code without using goto<\/em>, do it! I have my own solution for the McNuggets problem, which doesn’t use goto<\/em>, so i know it can be done. I reveal my method in next week’s Lesson<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" Leave to mathematicians to destroy something innocent like the number of nuggets that come in a McDonald’s Chicken McNuggets box. Continue reading 2020_11_28-Lesson.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n\r\nint main()\r\n{\r\n int max = 0, i = 0, sixes, nines, twenties;\r\n \r\nloopstart: while (i < 100)\r\n{\r\n for (sixes = 0; sixes*6 < i; sixes++)\r\n {\r\n if (sixes*6 == i)\r\n {\r\n i++;\r\n goto loopstart;\r\n }\r\n for (nines = 0; nines*9 < i; nines++)\r\n {\r\n if (sixes*6 + nines*9 == i)\r\n {\r\n i++;\r\n goto loopstart;\r\n }\r\n for (twenties = 0; twenties*20 < i; twenties++)\r\n {\r\n if (sixes*6 + nines*9 + twenties*20 == i)\r\n {\r\n i++;\r\n goto loopstart;\r\n }\r\n }\r\n }\r\n }\r\n max = i;\r\n i++;\r\n}\r\n \r\n printf(\"Maximum non-McNuggets number is %d\\n\", max);\r\n \r\n return 0;\r\n}<\/pre>\nMaximum non-McNuggets number is 43<\/code><\/p>\ni<\/code> through 100 in various permutations of 6, 9, and 20. This approach is logical, but can it be done without using the despised goto<\/em> statements?<\/p>\n