C StringsBy Dag, on December 30th, 2016
My notes about using C-type strings.
Static Character Arrays
/* * The most common way of creating a string. This declaration will create a * static sized buffer that may contain up to 50 characters, but not more. */ // Declaration char szString; // Initialization /* * This initialization will fill the array with nulls. This is only necessary * if the array will be fed a string without a null character. A null character * (or null terminator) is just an escaped zero '\0'. A char array does by * default contain garbage data, which will be printed with the string unless * it's null terminated. */ memset(szString, 0, sizeof(szString));
String Literals / String Constants
/* * Another common way of creating a string. This one is static, and cannot * be changed. The program will create this string somewhere in read-only * memory, and only give the starting address to the pointer variable. The * string will automatically be created with a null character at the end. * The pointer can be given a new string at any time, but the old one will * keep floating around in memory, and a dynamicly sized array (malloc) or * a static char array will be best suited for strings that will change a * lot. */ // Declaration and initialization char* szString = "This is a string literal. " "Also known as a string constant."; /* * This way of creating a string is good for when it's needed to create a * constant string that's not going to change, like a #define, only being * able to create it later during the program life span, conditionally. */
Dynamic Character Arrays
/* * Just like static character arrays, only with dynamic sizes. Good for * perfectionists that don't want to waste a single byte! The array will * be declared with the function malloc(), and can be freed with free(). * Then it can be declared again, with a new size. */ // Declaration char *szString; szString = (char *)malloc(50 * sizeof(char)); // Initialization memset(szString, 0, sizeof(szString)); // Applying a string, that you can manage like with a normal array. strcpy(szString, "Hello world."); // Careful with buffer overruns. // Replacing the period. szString = '!'; // Freeing memory and pointer for new use. free(szString);