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How to loop user input until datatype of the input?


Asked by Keenan Stout on Dec 05, 2021 FAQ



int number; bool check; do { Console.WriteLine ("Enter an integer:"); check = int.TryParse (Console.ReadLine (), out num1); } while (!check); This code will loop until the user has entered an integer number. This way, the program doesn't simply report an error, but instead immediately allows the user to input again another, correct value.
Likewise,
The user is then given a 'grade' that depends on the value of the letter choices. The program will loop until the user chooses to quit and end the program. If the user gives an invalid input, (any other character or letter not A-F), the program will loop, asking for valid input until it's given.
Additionally, While Loops and Input¶. While loops are really useful because they let your program run until a user decides to quit the program. They set up an infinite loop that runs until the user does something to end the loop. This section also introduces the first way to get input from your program's users.
Consequently,
If the user gives an invalid input, (any other character or letter not A-F), the program will loop, asking for valid input until it's given. After the program runs all the way through, and the user gets their results, the user clears the screen by hitting enter and the program starts again from the beginning.
In this manner,
A while loop can be used to read from input a sequence of data, and to stop reading from input as soon as a certain condition becomes true. This is typically an indefinite loop . Example: Read from input a set of strings and print them out on video until the user decides to stop.