Ex2+T2+Question+1

**Fill in the following theory parts:**
** What is a variable, why do we need them, how do we use them and for what? ** **- A variable ** **is a value determined by the introduction of a number.** - There are different types of data to set in the variable as: decimal, int, char, string, double or float. **  ·  What is casting and why is it used? ** **- It's how you change a type of variable or data into other type,** **such as Int32.Parse(tb1.Text). The number will change automatically at any time by just giving the instruction once.**
 * -You should give a name to the variable.
 * - Each leeter in a variable means a number, this is useful because you dont have to write the whole number.
 * · What is an if statement, for what do we use it and how does it works. **
 * -An if statement is a condition you give to the program for achieving a instruction** **, the program will ract different accorging to the given condition and situation.**

· **What is the difference between an If statement and an If/Else statement** **An else statement, reacts when the principal statement doesn't work. It can work as an alternative in case the principal operation can't be done, ELSE looks for another option that opperates the problem. An if statement, makes another action on the principal operation, for example: if the number is "0", show that you are a dog.** · ** How do we use a MessageBox A message box is usually used when the program can not do certain task, to give feedback to the user; this feedback could include a number or a text. This text box will appear on different situatuions For example: if the program can't read float numbers, the program will know this is an error and a mesage box will appear to indicate so. ** · ** What are the operators, which operators can we use and for what? ** **- The operators are the different type of operations you can give to a variable in order to react with another variable. Some opperators are: *, +, -, =, /, %, ++; --; <=, >=, etc. To react, I mean to make a division or a substraction, a sum, etc. **