{"id":7226,"date":"2025-11-08T00:01:36","date_gmt":"2025-11-08T08:01:36","guid":{"rendered":"https:\/\/c-for-dummies.com\/blog\/?p=7226"},"modified":"2025-11-01T13:10:53","modified_gmt":"2025-11-01T20:10:53","slug":"having-fun-with-goto-solution","status":"publish","type":"post","link":"https:\/\/c-for-dummies.com\/blog\/?p=7226","title":{"rendered":"Having Fun with goto<\/em> – Solution"},"content":{"rendered":"

This month’s C programming Exercise<\/a> is probably the most bizarre one I’ve ever offered! Using the goto<\/em> keyword is frowned upon, which means that your C programmer brain is unaccustomed to thinking about using goto<\/em> to construct, well, anything!
\n
\nFor me, it’s been a while since I coded in BASIC, which uses a GOTO<\/code> command to hop around the code. More relevant, however, is Assembly language: Assembly uses “jump” operands as branching instructions. In fact, the goto<\/em> format in C heavily resembles the jump operand format used in Assembly. So this type of challenge may have been a bit easier for me to code, though it’s still weird.<\/p>\n

Here is my solution:<\/p>\n

2025_11-Exercise.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n\r\nint main()\r\n{\r\n    int a = 0;\r\n    char b = 'A';\r\n\r\noutput:\r\n    if( a==10 ) goto end;\r\n    printf(\"%c%d  \",b,a);\r\n    b++;\r\n    if( b=='K' )\r\n    {\r\n        putchar('\\n');\r\n        a++;\r\n        b='A';\r\n    }\r\n    goto output;\r\n\r\nend:\r\n    return 0;\r\n}<\/pre>\n
This code doesn’t even look like C — but it is!<\/p>\n
The first label is output<\/code>, which is kinda the start of the outer nested loop. It’s followed by an if<\/em> statement to test the value of variable a<\/code>. When a<\/code> is equal to 10, execution branches to the end<\/code> label, the program is done. Otherwise, the program outputs the values of variables b<\/code> and a<\/code>, which have been initialized to ‘A’ and zero, respectively.<\/p>\n
Variable b<\/code> tracks the inner loop. An if<\/em> test determines when b<\/code> is equal to ‘K’. If true, the newline is output, variable a<\/code> is incremented (for the next row of output), and variable b<\/code> is reset back to the value ‘A’.<\/p>\n
When variable b<\/code> is less than ‘K’, a goto<\/em> statement jumps execution back to the output<\/code> label, where the process repeats.<\/p>\n
Here is sample output, which is identical to the (more proper) nested loop version of the code:<\/p>\n
A0  B0  C0  D0  E0  F0  G0  H0  I0  J0  
\nA1  B1  C1  D1  E1  F1  G1  H1  I1  J1  
\nA2  B2  C2  D2  E2  F2  G2  H2  I2  J2  
\nA3  B3  C3  D3  E3  F3  G3  H3  I3  J3  
\nA4  B4  C4  D4  E4  F4  G4  H4  I4  J4  
\nA5  B5  C5  D5  E5  F5  G5  H5  I5  J5  
\nA6  B6  C6  D6  E6  F6  G6  H6  I6  J6  
\nA7  B7  C7  D7  E7  F7  G7  H7  I7  J7  
\nA8  B8  C8  D8  E8  F8  G8  H8  I8  J8  
\nA9  B9  C9  D9  E9  F9  G9  H9  I9  J9  <\/code><\/p>\n
I hope that you can see how goto<\/em> made a nested loop not look like a nested loop. The code above still has a poetic beauty to it, but its purpose is obfuscated. Even an experienced programmer must step through the code line by line to determine what exactly is going on.<\/p>\n
Remember that your solution need not look exactly like mine. In fact, if you have a different solution, consider pasting it in the comments. Use the <pre><\/code> tags to ensure that the formatting doesn’t go all bonkers.<\/p>\n","protected":false},"excerpt":{"rendered":"
This month’s C programming Exercise is probably the most bizarre one I’ve ever offered! Using the goto keyword is frowned upon, which means that your C programmer brain is unaccustomed to thinking about using goto to construct, well, anything!<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-7226","post","type-post","status-publish","format-standard","hentry","category-solution"],"_links":{"self":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7226","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7226"}],"version-history":[{"count":6,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7226\/revisions"}],"predecessor-version":[{"id":7243,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7226\/revisions\/7243"}],"wp:attachment":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7226"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}