{"id":6553,"date":"2024-09-08T00:01:34","date_gmt":"2024-09-08T07:01:34","guid":{"rendered":"https:\/\/c-for-dummies.com\/blog\/?p=6553"},"modified":"2024-10-01T10:23:06","modified_gmt":"2024-10-01T17:23:06","slug":"describing-complex-data-solution","status":"publish","type":"post","link":"https:\/\/c-for-dummies.com\/blog\/?p=6553","title":{"rendered":"Describing Complex Data – Solution"},"content":{"rendered":"

In the C language, a structure is used to express complex data types. The structure contains members that describe different parts of this complex data, such as a matrix required in this month’s Exercise<\/a>.
\n
\nFor my solution, I created the following structure.<\/p>\n

struct matrix {
\n    int *grid;
\n    int columns;
\n    int rows;
\n};<\/code><\/p>\n

The structure contains three members: grid<\/code> is a pointer, the base of an array that contains the matrix’s data (integers); columns<\/code>, the number of columns; and rows<\/code>, the number of rows. Together, rows<\/code> × columns<\/code> defines the size of the matrix.<\/p>\n

It’s possible to assign a single-dimension array to a pointer, which makes it easy to create this structure using the two matrixes presented in the challenge post. Here is my solution, including the output()<\/em> function:<\/p>\n

2024_09-Exercise.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n\r\nstruct matrix {\r\n    int *grid;\r\n    int columns;\r\n    int rows;\r\n};\r\n\r\nvoid output(char *title,struct matrix m)\r\n{\r\n    int x,y;\r\n\r\n    puts(title);\r\n    for( y=0; y<m.rows; y++ )\r\n    {\r\n        for( x=0; x<m.columns; x++ )\r\n        {\r\n            printf(\" %3d \",*(m.grid+x+y*m.columns) );\r\n        }\r\n        putchar('\\n');\r\n    }\r\n}\r\n\r\nint main()\r\n{\r\n    int matrix_a[12] = {\r\n        10, 20, 30, 40,\r\n        11, 21, 31, 41,\r\n        12, 22, 32, 42\r\n    };\r\n    int matrix_b[4] = {\r\n        1, 2,\r\n        3, 4\r\n    };\r\n    struct matrix a = { matrix_a, 4, 3 };\r\n    struct matrix b = { matrix_b, 2, 2 };\r\n\r\n    \/* output each matrix *\/<\/span>\r\n    output(\"Matrix A\",a);\r\n    output(\"Matrix B\",b);\r\n\r\n    return 0;\r\n}<\/pre>\n
Each matrix is defined as an integer array in the main()<\/em> function. The next two statements assign values to the matrix structures a<\/code> and b<\/code>:<\/p>\n
struct matrix a = { matrix_a, 4, 3 };
\nstruct matrix b = { matrix_b, 2, 2 };<\/code><\/p>\n
My version of the output()<\/em> function has two arguments: The first is a title string, the second the structure defining the matrix. The function outputs the title first, then uses a nested loop to output the rows and column values.<\/p>\n
To find offsets in the array, which is now a pointer, the following expression is used:<\/p>\n
*(m.grid+x+y*m.columns)<\/code><\/p>\n
The row values are held in m.rows<\/code>, which defines the outer loop (variable y<\/code>). Each row consists of column values stored in m.columns<\/code>. The values are offset from the array’s base, m.grid<\/code>. Add the row offset plus the row count times the number of columns to obtain each element in the matrix.<\/p>\n
Here’s the output:<\/p>\n
Matrix A
\n  10   20   30   40 
\n  11   21   31   41 
\n  12   22   32   42 
\nMatrix B
\n   1    2 
\n   3    4 <\/code><\/p>\n
I hope your solution met with success and you’re able to use a structure to describe a matrix. By using this technique, you can manipulate the matrix in various ways without having to rely upon or assume that the grid is square.<\/p>\n
For next month’s Exercise<\/a>, I continue this exploration with some matrix manipulation.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the C language, a structure is used to express complex data types. The structure contains members that describe different parts of this complex data, such as a matrix required in this month’s Exercise.<\/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-6553","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\/6553","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=6553"}],"version-history":[{"count":5,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/6553\/revisions"}],"predecessor-version":[{"id":6617,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/6553\/revisions\/6617"}],"wp:attachment":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6553"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6553"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6553"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}