\nIn yesterday’s post, which was about Perl subroutines, I introduced an example program that calculates the final price of an item from its sticker price, the discount, and the tax rate.<\/p>\n
In my context, anyway, the program works great – but any zealots who typed and ran it on Boxing Day noticed that it does not format the answers as a cash register would. For example, if you give it the inputs<\/p>\n
price: 78
\ndiscount: 33
\ntax rate: 12<\/p>\n
it will give back<\/p>\n
final price: 58.5312<\/p>\n
Prices are given to two decimal places, not four. How can the program be fixed to give answers formatted as from a cash register?<\/p>\n
Perl has two answers to this problem: printf(format<\/em>, number<\/em>) and sprintf(format<\/em>, number<\/em>). Today, we’ll look at a few lines of code that show the use of these built-in functions:<\/p>\n Let’s compare sprintf and printf. Both leave the input number unchanged. The function sprintf reformats it, and saves the reformatted number in a new variable. The function printf simply prints the number in the specified format.<\/p>\n I wish all of you the best of nights:)<\/p>\n Source:<\/p>\n McGrath, Mike. Perl in easy steps<\/em>. Southam: Computer Step, 2004.<\/p>\n
\n#!\/usr\/bin\/perl<\/br>
\nprint “Enter a number, please.”;
\nprint “This program will round your number to two decimal places.”;
\n$num=<STDIN>;
\n$rounded=sprintf(“%.2f”,$num);
\nprint “Using printf, your number, rounded to two decimal places, is “;
\nprintf(“%.2f”,$num);
\nprint “\\n\\nRecall: the number you entered is $num”;
\nprint “\\n\\nFrom sprintf, rounded to two decimal places, “;
\nprint “your number is $rounded”;<\/p>\n