Factor is a scary word, but not really a mathematical monstrosity. If you have an integer value, its factors are the other integers that can divide evenly into the original value. The computer can deftly discover these values, providing you give it the proper C code to munch upon.
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Author Archives: dgookin
A Weird Thing I’ve Never Seen Before
While browsing some sample code recently, I encountered the following C language expression:
x = &(*ptr);
Both variables x and ptr are pointers. So what the heck is going on?
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Looping with time_t values
In C, the time_t variable type is associated with the Unix epoch, or the number of seconds ticked since midnight, January 1, 1970. It’s typically a long int value, though as a typedef declaration, its specific data type could change in the future. Still, as a long int, you can play with it like other integers in your code.
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Time After Time
While writing some code recently, it became necessary to translate timestamp strings into time_t or epoch time values. This value is the number of seconds that have ticked since midnight, January 1, 1970. time_t values are stored long integers (generally), but I needed a utility to translate them into time strings. It turned out, such a tool wasn’t that difficult to create.
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The Leap Year Function – Solution
I’ve tackled the leap year program on this blog before. My Month Program series addressed the issue specifically. That code offers the february() function, which returns 28 or 29, depending on whether the current year is the leap year.
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Multiple Expressions in a for Condition
Every C programmer has screwed up a for loop’s statement. Having three arguments in one set of parentheses is just begging for trouble. That’s a lot of yard waste, but there’s a reason for all the detritus.
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The Leap Year Function
My brain’s algorithm for determining whether the current year is a leap year is based on US Presidential elections. They always happen on a leap year. Or do they?
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Radians to the Rescue!
The word radian comes from radius, which is half the diameter of a circle. If you take a radius and create an arc along the circle of the same length, you get one radian.
Okay. So what?
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What the Heck is a Radian?
Math should be fun. My observation is that it’s not taught correctly in school, so generations of students get an education, but are weak in math. I’m one of them. As I’ve aged, I’ve grown fond of math, but still struggle with it. That’s disappointing because so much of math is actually kind of cool, just not explained well.
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Marching Through an Array in Memory
C language pointers are smarter than the old BASIC peek and poke commands. A pointer knows the the type of value it’s referencing in memory, specifically how large the value is or how many bytes of storage it occupies. You can use the Code::Blocks debugger to witness such pointer intelligence.
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