What is a String?
Note that along with C-style strings, which are arrays, there are also string literals, such as "this". In reality, both of these string types are merely just collections of characters sitting next to each other in memory. The only difference is that you cannot modify string literals, whereas you can modify arrays. Functions that take a C-style string will be just as happy to accept string literals unless they modify the string (in which case your program will crash). Some things that might look like strings are not strings; in particular, a character enclosed in single quotes, like this, 'a', is not a string. It's a single character, which can be assigned to a specific location in a string, but which cannot be treated as a string. (Remember how arrays act like pointers when passed into functions? Characters don't, so if you pass a single character into a function, it won't work; the function is expecting a char*, not a char.)
To recap: strings are arrays of chars. String literals are words surrounded by double quotation marks.
"This is a static string"
Remember that special sauce mentioned above? Well, it turns out that C-style strings are always terminated with a null character, literally a '\0' character (with the value of 0), so to declare a string of 49 letters, you need to account for it by adding an extra character, so you would want to say:
char string[50];
This would declare a string with a length of 50 characters. Do not forget that arrays begin at zero, not 1 for the index number. In addition, we've accounted for the extra with a null character, literally a '\0' character. It's important to remember that there will be an extra character on the end on a string, just like there is always a period at the end of a sentence. Since this string terminator is unprintable, it is not counted as a letter, but it still takes up a space. Technically, in a fifty char array you could only hold 49 letters and one null character at the end to terminate the string.
No comments:
Post a Comment