If an object that has static storage duration is not initialized explicitly, then: if it has pointer type, it is initialized to a null pointer; if it has arithmetic type, it is initialized to positive or unsigned zero; if it is an aggregate, every member is initialized recursively according to these rules; if it is a union, the first named member is initialized recursively according to these rules.
Improve this answer. Community Bot 1 1 1 silver badge. Matteo Italia Matteo Italia k 17 17 gold badges silver badges bronze badges. Watch better: str2 which points to a string literal is not modified, and str3 is allocated on the stack or somewhere else, depending on where that code is put , the literal is just for initialization.
The literal is used for initialization, it's copied in the buffer str3 , which is automatically sized by the compiler to accommodate that string. Look e. EboMike: str3 has type char[] which becomes complete once it is initialised with the string literal to char[38]. This type is a modifiable lvalue. You are not modifying the string literal, you are modifying an lvalue that has the same type and contents as the string literal.
Successive characters of the character string literal including the terminating null character if there is room or if the array is of unknown size initialize the elements of the array. At the end of its initializer list, the array no longer has incomplete type.
I should have looked closer! Show 4 more comments. It is considered best practice to initialize a variable at the point of declaration. For example if later in your code you do if str! Maybe you said "best practice" rather than "good practice"?
I don't know, I don't see how what you said justifies that down vote. This clutters up code with a bunch of worthless setting and checking of pointer values. EdwardHartnett, no it doesnt. I did not advocate any checking of anything.
I advocated getting into the habit of initializing at the point of declaration. Max Max This means that you can choose: if you know that you will allocate it shortly after its declaration you can avoid setting it as NULL this is a sort of rule to thumb in any other case, if you want to be sure, just do it. The only real problem occurs if you try to use it without having initialized it. Jack Jack k 28 28 gold badges silver badges bronze badges.
Don't initialise all your pointer variables to NULL on declaration "just in case". Martin Broadhurst Martin Broadhurst 8, 2 2 gold badges 26 26 silver badges 34 34 bronze badges. Let me rephrase: "The compiler will warn you about something IF you ask it to warn you about that thing. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article. Related Articles : puts vs printf to print a string Swap strings in C Storage for strings in C gets is risky to use!
The destination array must be large enough to hold the combined strings including the null character. If it is not, the array will overflow. In both cases, the string is passed or returned by address.
The string class has several constructors that may be called explicitly or implicitly to create a string object. The data member p is a pointer to contains the address of the first character in a dynamically-allocated array of characters. The data member length contains the length of the string. The data member capacity contains the number of valid characters that may currently be stored in the array.
The subscript specified inside the brackets is passed as an argument to the member function, which then returns the character at that position in the string.
Both of methods return an unsigned int , the number of valid characters in the string not including the null character. All such relational expressions resolve to the Boolean values true or false.
This results in a copy of the string object being created. In order to read a string contains spaces, we use the gets function. Gets ignores the whitespaces. It stops reading when a newline is reached the Enter key is pressed. Another safer alternative to gets is fgets function which reads a specified number of characters.
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