Visual Basic .NET/Assignation and comparison operators

Assignment The "=" operator is used for assignment. The operator also serves as a comparison operator (see Comparison). To set values: x = 7 ' x is now seven; in math terms we could say "let x = 7" x = -1294 x = "example" You can use variables in the equal operator, as well. Dim x As Integer Dim y As Integer = 4 x = y ' Anywhere we use x, 4 will be used. y = 5 ' Anywhere we use y, 5 will be used, x stays to 4 Comparison The "=" operator is used for comparison. The operator also serves as a assignation operator (see Assignment). To compare values: If 4 = 9 Then ' This code will never happen: End ' Exit the program. End If If 1234 = 1234 Then ' This code will always be run after the check: MessageBox.Show("Wow! 1234 is the same as 1234.") ' Create a box in the center of the screen. End If You can use variables in the equal operator, as well. If x = 4 Then MessageBox.Show("x is four.") End If Let's try a slightly more advanced operation. MessageBox.Show("Seven equals two is " & (7 = 2) & ".") ' The parentheses are used because otherwise, by order of operations (equals is ' processed last), it would be comparing the strings "Seven equals two is 7" and "2.". ' Note here that the & operator appends to the string. We will talk about this later. ' ' The result of this should be a message box popping up saying "Seven equals two is ' False." This is because (7 = 2) will return False anywhere you put it. In the ' same sense, (7 = 7) will return True: MessageBox.Show("Seven equals seven is " & (7 = 7) & ".") You will get an error if you try to assign a constant or a literal a value, such as 7 = 2. You can compare 7 and 2, but the answer will always be False. In the case of two equal operators appearing in a statement, such as Dim x As Boolean x = 2 = 7 The second equal operator will be processed first, comparing 2 and 7, giving a False. Then the first equal operator will be processed, assigning False to x. More Comparison Operators (x < y) (x > y) (x <> y) (x <= y) (x >= y) (x less than y), (x more than y), (x not equal to y), (x less than or equal y) & (x greater than or equal to y) Note the way round the operators are on the last two, putting them the other way round is not valid. fr:Visual Basic .NET/Assignation et comparaison