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Only global/static variables are, local variables aren't.
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∙ 2011-11-17 08:59:10
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What is the default value of integer in c?
For static and global variables it is 0; automatic variables are not initialized by default.in the c language there is no default value for non static local variables. The variable holds whatever was in memory before it became a variable. It's best to always initialize a non static local variable before using it in the c language (or at least before comparing it to something else). Also It's best to assume that there is no default value because this varies from language to language, and hardware to hardware.Cheers!
What are storage classes in c?
There are four types of storage classes in c. It defines the scope and lifetime of a variable or function.1. auto - This is the default storage class inside a function. Auto can only be used with in functions. i.e. only for local variables, not for globals.2. register - The variables declared using the register storage class may stored in CPU registers instead of RAM. Since it doesn't have a memory location, the '&' operator for getting the address of the variable cannot be applied (in C). This storage class cannot be used for global scope data.3. static - In case of local variable, it is initialized at compile time and retains its value between the calls. By default the static variables will be initialized to zero, in case of pointer variable initialized to NULL.4. extern - Refers to a public variable defined somewhere else (often in a different source file.)
What is auto declaration in C?
Auto is one of the four storage classes in c. This is the default storage class. The auto storage class can be used only inside functions, i.e. only to declare local variables and not to declare global variables. All the local variables are by default auto variables. Other storage classes are: Register - variables declared may get stored in CPU registers instead of RAM Static - default storage class for global variables extern - defines global variables that is visible to all object modules
Why static variables are initialized to zero?
When a variable is declared, your computer assigns a section of memory to that variable. If the variable isn't initialized, there's no way of knowing what data is already stored in that section of memory, which can cause errors in your programs. In managed languages, such as C#, this is done automatically at declaration. Although it's still good practice to initialize variables yourself.
How is a structure initialized?
In C, structures are uninitialized by default. To initialize a structure you will typically zero the memory allocated to the structure and then set specific members to specific values. If all members are non-zero, you can simply set those members rather than zero the memory first. In C++, structures are initialized via inline initializes and/or through the class constructor.
What is the default value of integer in c?
For static and global variables it is 0; automatic variables are not initialized by default.in the c language there is no default value for non static local variables. The variable holds whatever was in memory before it became a variable. It's best to always initialize a non static local variable before using it in the c language (or at least before comparing it to something else). Also It's best to assume that there is no default value because this varies from language to language, and hardware to hardware.Cheers!
What is the default value of int in c?
I'm not sure. I have written C programs in which the default value was what ever happened to be in the variable's memory location when the space was allocated. So it could be 0. Or it could be anything. That is why it is always important to initialize variables when using C. I don't know if this is true with modern C compilers. No default value for automatic variables, 0 for others.
What are the value and preference of global variable?
Global variables can have any value, in C they are aumaticatically initialized to zero.
What are storage classes in c?
There are four types of storage classes in c. It defines the scope and lifetime of a variable or function.1. auto - This is the default storage class inside a function. Auto can only be used with in functions. i.e. only for local variables, not for globals.2. register - The variables declared using the register storage class may stored in CPU registers instead of RAM. Since it doesn't have a memory location, the '&' operator for getting the address of the variable cannot be applied (in C). This storage class cannot be used for global scope data.3. static - In case of local variable, it is initialized at compile time and retains its value between the calls. By default the static variables will be initialized to zero, in case of pointer variable initialized to NULL.4. extern - Refers to a public variable defined somewhere else (often in a different source file.)
What is auto declaration in C?
Auto is one of the four storage classes in c. This is the default storage class. The auto storage class can be used only inside functions, i.e. only to declare local variables and not to declare global variables. All the local variables are by default auto variables. Other storage classes are: Register - variables declared may get stored in CPU registers instead of RAM Static - default storage class for global variables extern - defines global variables that is visible to all object modules
Why static variables are initialized to zero?
When a variable is declared, your computer assigns a section of memory to that variable. If the variable isn't initialized, there's no way of knowing what data is already stored in that section of memory, which can cause errors in your programs. In managed languages, such as C#, this is done automatically at declaration. Although it's still good practice to initialize variables yourself.
Difference between variables and constants in C plus plus?
A constant variable cannot be changed after it is initialized, whereas a normal variable can.ex:int main(){const float pi = 3.14159;int non_const = 0;non_const = 42; // legalpi = 3; // illegal, this should generate a syntax error when you compilereturn 0;}
What do you mean by initialization in c plus plus?
Not initialized variable: int myInt; Initialized variable: int myInt = 10;
What is constant variable in c?
Constant variables refers to those variables whose values cannot be changed. These variables should be initialized along with their declaration. Attempt to change the value of a constant variable will generate compile error. The syntax for declaring a constant variable is:const data-type variableName = value;
How is a structure initialized?
In C, structures are uninitialized by default. To initialize a structure you will typically zero the memory allocated to the structure and then set specific members to specific values. If all members are non-zero, you can simply set those members rather than zero the memory first. In C++, structures are initialized via inline initializes and/or through the class constructor.
What happens when variables are not properly initialized?
In C, uninitialized variables may contain any value, usually whatever happened to be in the same memory location before the memory was allocated to that function. This is a likely source of bugs, since it means that whatever the programmer meant for the variable to contain was not in it.
Do variables that are declared but not initialised contain garbage values?
It depends on the language. In C and C++, all static variables are zero-initialised at runtime but local variables are not, thus an uninitialised local variable will hold whatever value happens to reside at the memory allocated to the variable at runtime. However, the C/C++ compiler can be configured to warn against using an uninitialised variable. In object oriented languages like Java there's no such thing as an uninitialised variable. This is because all Java variables are objects so we must pass the initial value to the object's constructor unless the object has default constructor. Attempting to default construct an object that has no default constructor is a syntax error.
