Trying to salve my frustration with the scanf() function, I decided in last week’s Lesson to try to use scanf() to build a string. Because the function terminates standard input at the first whitespace character (space, tab, newline), the strings input must be stored and the string built in memory.
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Author Archives: dgookin
The Sum of the Integer’s Digit – Solution
The challenge for this month’s Exercise is to tally the digits in an integer, reporting the sum. You must use math and not cheat by looking at the old solution, which I didn’t. Promise.
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Using scanf() to Build a String – Part I
The scanf() function is useful for teaching, but it’s a booger. I avoid it outside of demonstration purposes. But it does provide good fodder for training beginning programmers to think about stream I/O.
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Tally the Digits, Again
Difficulty: ★ ★ ☆ ☆
Seven years ago (to this same date!) I wrote an Exercise to tally the digits in a number. The solution required that the sum be reduced to a single digit. For example, the sum of digits in 12345 is 15, which is then reduced to six.
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The Sum of the Integer’s Digit Is . . .
Difficulty: ★ ★ ☆ ☆
Yes, this Exercise has been done before. But back then, exactly seven years ago, I had the digits reduced further so that the result was a single digit. This time, your goal is to tally the digits in an integer and report the results — no reductions!
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Outputting a Key Value
The power of an associative array is that it uses keys, text or numbers, to reference values. Know the key and you can fetch the value . This “association” works like an array in C, where you know the index or offset for an element. Though with an associative array, the index is a value or string — the key.
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Dumping a Phony Associative Array
The first phony associative array function I need to write is a simple dump: Output the array’s contents in the form of pairs. Performing this operation requires a bit of manipulation to the way the array is presented in the code.
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Associative Arrays
Being the ancient and venerable programming language it is, C lacks the associative array data type. This type of array is found in other languages, and it can be awkwardly simulated in C.
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Swapping Variables – Solution
This month’s Exercise challenges you to swap two variables’ values without using a third variable. It’s a solution widely available on the Internet, but your job is to figure out the technique without looking elsewhere.
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Pairs of Arrays
I enjoy studying foreign languages. A tool like Google Translate comes in handy, but it’s not perfect. That’s because computers translate words and phrases, but not the living, spoken language. Regardless, I thought I’d give language translation a stab, which got me into the topic of exploring arrays.
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