What is the difference between variable declaration and variable definition in C?

• Local variable
• Global variable
• Environment variable

• The variables which are having scope/life only within the function are called local variables.
• These variables are declared within the function and can’t be accessed outside the function.

• The variables which are having scope/life throughout the program are called global variables.
• Global variable is defined outside the main function. So, this variable is visible to main function and all other sub-functions.

• Environment variable is a variable that will be available for all C applications and C programs.
• Once environment variables are exported, we can access them from anywhere in a C program without declaring and initializing in an application or C program.

• The symbols which are used to perform logical and mathematical operations in a C program are called C operators.
• These C operators join individual constants and variables to form expressions. Operators, functions, constants and variables are combined together to form expressions.

• The symbols which are used to perform logical and mathematical operations in a C program are called C operators.
• These C operators join individual constants and variables to form expressions. Operators, functions, constants and variables are combined together to form expressions.

Ternary operator is same as if else control statement in C.

Syntax : (Condition? true_value: false_value);

Example: (A > 100? 0: 1);

• C Arithmetic operators are used to perform mathematical calculations like addition, subtraction, multiplication, division and modulus in C programs.
• Arithmetic operators are +, -, *, /, %

• Assignment operators are used to assign the values to the variables.
• Assignment operators are =, +=, -=, /+, %= etc.

• Relational operators are used to find the relation between two variables. i.e. to compare the values of two variables in a C program.
• Relational operators are >, <, >=, <=, ==, !=