Programming in C · topic
Array to pointer decay and its exceptions, sizeof traps, array parameters, two-dimensional arrays with row-major address arithmetic, character arrays versus string literals, sizeof versus strlen and the common string library functions.
Array to pointer decay and its three exceptions, the identities a[i] = *(a + i) = i[a], partial initialisation, a versus &a versus &a[0], sizeof of arrays and of array parameters, two-dimensional arrays as arrays of rows with types and strides, row-major and column-major address formulas with lower bounds and computed examples, passing a 2-D array to a function, and the solved GATE CS 2019 Q.24.
A partial preview of the top of the sheet. The full sheet is in the Programming in C cheat sheet pack.
![int a[3][4] drawn as a 3 by 4 grid of byte offsets 0 to 44, with a[1][2] at offset 24 highlighted, and the same array as one strip of three 16-byte rows with markers a at 0, a+1 at 16, a+2 at 32 and &a+1 at 48.](https://bywjbbkinjqiyalvzqfd.supabase.co/storage/v1/object/public/sheet-media/PCC/PCC-15/diagrams/PCC-15.d01.webp)
Strings as null-terminated character arrays, string literals versus modifiable char arrays, a byte picture of three ways to hold the same text, sizeof versus strlen including embedded null bytes, strlen, strcpy, strcat, strcmp, strncpy, strchr and strstr with their traps, pointer offsets into a literal, a hand-written length and reverse, and the undefined cases: modifying a literal and reading an array with no terminator.
A partial preview of the top of the sheet. The full sheet is in the Programming in C cheat sheet pack.
![Three ways to hold the string GATE: char s[10] holds G A T E and six null bytes; char t[] holds G A T E and one null byte; const char *p is a pointer cell whose arrow leads to the 5-byte literal, which must not be modified.](https://bywjbbkinjqiyalvzqfd.supabase.co/storage/v1/object/public/sheet-media/PCC/PCC-16/diagrams/PCC-16.d01.webp)
