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HOW DO WE VALIDATE USER INPUT IN PROGRAMMING?
                 Data validation is the process of ensuring that the data entered by the user is valid. Consider

                 an example, if someone asks you, “What did you have today for lunch?” You are supposed
                 to answer the person what food item you had for lunch. Suppose you answer “I have a red
                 box in my hand”. This is not an acceptable answer to the question which was asked.

                 In the same way, in programming, when you create a variable with a specific data type,
                 and the user is supposed to enter a certain value in that data type, you should make sure

                 that the user enters the right type of value, which did not cause any error during program
                 execution. This validation of Input plays a vital role while writing a program.

                 For validating the input entered by the user, the most common practice is to set a flag which
                 shows the value as ‘true’ and ‘false’. The default value of flag is ‘false’.
                    If the value entered by the user matches with the expected value, the flag will be reset
                     to ‘true’ and the program is executed.

                    If the value entered by the user does not matches with the expected value, the flag will
                     be reset to ‘false’ and an error message is shown.

                                          Coding fact


                   Elon Musk is the CEO of Tesla Motors and SpaceX, two of the most influential
                   tech industries of the current times. He was also an inspiration for the Iron Man.




                 MATH OPERATIONS IN PROGRAMMING

                 Variable is  a  name  given  to  a  storage area which  defines  the  size,  layout,  range  set  of
                 operations to be performed on the variable.

                 Once you declare the data types, you will learn to perform the operations on the data types.
                    Operator: It is a symbol which operates on a value assigned to a variable. Example: +,-,

                     *, \.
                    Operand: It is a value on which the operator performed an operation.


                 Arithmetic operations
                 Arithmetic  operation  uses  arithmetic operators to  combines  two  or more numeric
                 expressions. The arithmetic operators perform operations such as: addition, subtraction,

                 multiplication, division, and modulus. In the table given below, we are taking the value of
                 variable a=10, and b=30.






                                                                                          Variables in Real Life   11
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