The classic paradigm for swapping values between two variables involves using a third variable. But is the third variable even necessary? At the end of the operation, the values of variables It turns out you need only two variables to swap their values — odd as it sounds. The process involves a bit of math and some head scratching, but it works. Rather than rush to StackOverflow for the answer, try on your own to think of a way to swap two variables’ values, which is the challenge for this month’s Exercise.<\/p>\n Here’s a skeleton to get you started:<\/p>\n As the code stands now, two values are fetched from standard input. Both are output, then comes the swap (the part you write) and the results are output:<\/p>\n Your challenge is to add code after the comment, fancy math stuff that swaps the values without adding a third variable. In fact, as a hint, you need three lines of code (three statements) just as if you were using a third variable.<\/p>\n Here is the output from my solution:<\/p>\n Please O please do try this exercise on your own. The solution is widely available on the interwebs, but I had a good time trying to make the swap happen without cheating. You can view my solution here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" Can you put the value of
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\nFor example, to swap a<\/code> and b<\/code>, you use variable c<\/code>:<\/p>\nc = a;
\na = b;
\nb = c;<\/code><\/p>\na<\/code> and b<\/code> are swapped, with variable c<\/code> left with nothing else to do. But is variable c<\/code> even necessary?<\/p>\n2023_06_01-Lesson.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n\r\nint main()\r\n{\r\n int a,b;\r\n\r\n printf(\"Enter value A: \");\r\n scanf(\"%d\",&a);\r\n printf(\"Enter value B: \");\r\n scanf(\"%d\",&b);\r\n\r\n printf(\"Before: A=%d, B=%d\\n\",a,b);\r\n\r\n \/* swap variables *\/<\/span>\r\n\r\n printf(\"After: A=%d, B=%d\\n\",a,b);\r\n\r\n return(0);\r\n}<\/pre>\nEnter value A: 10
\nEnter value B: 45
\nBefore: A=10, B=45
\nAfter: A=10, B=45<\/code><\/p>\nEnter value A: 10
\nEnter value B: 45
\nBefore: A=10, B=45
\nAfter: A=45, B=10<\/code><\/p>\na<\/code> into b<\/code> when using only these two variables? Continue reading