CODEWITHSUNDEEP
carraysassign
Null Spark
Null Spark

Reputation: 409

Cannot edit a C array by index

I am a noob to C programming (I come from the lands of JS and PHP), and as a learning exercise I attempted to write a program that asks for the user's name, and then prints it back out with the small exception of changing the first letter to a z. However, when I went to compile the code it returned the following error message in reference to the line name[0] = "Z";

warning: assignment makes integer from pointer without a cast

Is there a reason I can't assign a value to a specific index in a char array?

(Note: I have tried typecasting "Z" to a char but it just threw the error

warning: cast from pointer to integer of different size`)

Upvotes: 0

Views: 156

Answers (3)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726809

Unlike some languages that do not distinguish between strings and characters, C requires a different syntax for characters (vs. a single-character string).

You need to use single quotes:

name[0] = 'Z';

The error is quite cryptic, though. It is trying to say that "Z", a single-character C string, gets assigned to name[0], an integral type of char. C strings are arrays; arrays are convertible to pointers. Hence, C treats this as a pointer-to-int assignment without a cast.

Upvotes: 5

cs95
cs95

Reputation: 402813

In C, single quotes and double quotes carry different meanings. In fact, there is no concept of "Strings" in C. You have the basic char data type, where a char is represented by single quotes. To represent strings, you store them as an array of chars. For example, 

char text[] = {'h', 'e', 'l', 'l', 'o'};

This is just a more tedious way of writing 

char text[] = "hello";

This is exactly the same as the first example, with the exception that there is a null character \0 at the end (this is how C detects the end of "strings"). It's the same as saying char text[] = {'h', 'e', 'l', 'l', 'o', '\0'}; except now you can work with your array more easily, if you want to do string based processing on it.

Coming to your question, if you want to index a certain character in a "string", you'd need to access it by it's index in the array.

So, text[0] returns the character h which is of type char. To assign a different value, you must assign a single quoted char as so: 

text[0] = 'Z';

Upvotes: 2

BattleTested_закалённый в бою
BattleTested_закалённый в бою

Reputation: 4111

replace name[0] = "Z"; with name[0] = 'Z';.

'single-quatation' is for an character element and "double-quatation" is for a string assignment.

Upvotes: 4

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