Tag: variable declaration in c

Variable in C play an important role. It can also be said that variables are the backbone of many programming languages. Variables in C are used to store data in various formats. It stores all the data and acts as a memory card to use while the program is running. Different types of variables require different amounts of memory and there is a specific set of operations that can be applied to them. Rules for Defining Variables in C: C variables must not start with a number. Otherwise, the variable will not be valid. For example (a string is not a valid variable). Blank spaces are not allowed between variables. For example (string 1 is not valid, string_one is a valid variable). Keywords cannot be defined as variables. For example (para is not a valid variable as it is used as a keyword in C). C is a case-sensitive language, so use of upper and lower case is considered a different variable. For example (NUMBER and number are treated as two different variables in C). Variable names can be a combination of strings, numbers, and special characters such as underscores (_). Variable Declaration in C Language: A typical variable declaration has the form: data_type variable_name; where, data_type: Indicates the type of data to be stored. Data types include int, float, char, double, longint, and so on. variable_name: Indicates the name of the variable. It can be anything other than keywords. For example: Here Code: #include #include int main() { int m, n; m = 2; n = 3; z = m + n; printf("Sum of two numbers is: %d \n", z); return 0; } Initialize variables C Language: Initializing a variable in C means assigning a value directly to the variable as it is declared. The syntax is: data_type variable_name = value; For example: int a = 10; The variable "a" is created and initialized with a value of 10. More about this source text Here Code: #include #include int main() { int m = 2, n = 3; z = m + n; printf("Sum of two numbers is: %d \n", z); return 0; } Types of Variable in C Language: There are five types of variables declaration in C Language: 1. Local Variables: local functions can change the value of a variable and used within a function are called local variable and also must be declared only before they can be used. Example: Here Code: #include void function() { int x = 10; // local variable } int main() { function(); } In the above code, x can only be used within the scope of function (). An error will occur if it is used in the main function. 2. Global Variables: Variables declared outside of the function are called global variables. Any function can change the value of a variable. Example: Here Code: #include int x = 20;//global variable void function1() { printf("%d\n" , x); } void function2() { printf("%d\n" , x); } int main() { function1(); function2(); return 0; } In the above code, all functions can access the global variable, so both functions can use the global variable x. 3. Static variables: Variables declared with the static keyword are called static variables. Example: Here Code: #include void function(){ int x = 20;//local variable static int y = 30;//static variable x = x + 10; y = y + 10; printf("\n%d,%d",x,y); } int main() { function(); function(); function(); return 0; } In the example above, local variables always print the same value each time a function is called, while static variables print incremental values on each function call. 4. Automatic variables in C: All variables declared within a function are considered automatic variables by default. Example: Here Code: #include void function() { int x=10;//local variable (also automatic) auto int y=20;//automatic variable } int main() { function(); return 0; } In the example above, both x and y are automatic variables. The only difference is that the variable y is explicitly declared with the auto keyword. 5. External variables: External variables are declared using the extern keyword. ‘extern’ keyword can be used in C language. Example: Here Code: myfile.h extern int x=10;//external variable (also global) program1.c #include "myfile.h" #include void printValue(){ printf("Global variable: %d", global_variable); } In the example above, x is an external variable used by multiple files. Conclusion: In this article, you have learned how to implement them using declarations, initializations, syntax, and programs. We have also discussed the types of variables in C and the rules for defining them. Read More For Master The String in C Language References: https://www.tutorialspoint.com/cprogramming/c_variables.htm https://fresh2refresh.com/c-programming/c-variables/ https://www.studytonight.com/c/variables-in-c.php https://www.w3schools.in/c-tutorial/variables/

Tag: variable declaration in c

Variable Declaration in C

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