How can we validate input in C++ ?

Question

How can we validate input in C++?

Let me elaborate my question: Example I want to show an error saying "Name only contains alphabets" when the user types any number or any other character in the name field.

Answer 1

You can use regular expressions in c++ to validate input as per specific criteria.

You can learn about regex here :
https://www.sololearn.com/learn/9704/?ref=app

You need to include the 'regex' header in your code to be able to use regex statements :

#include <regex>

For your case, the regex will be declared like this :

regex pattern("[A-Za-z]+");

Then you can use regex_match for checking if a string satisfies your requirement :

string str = "Hello";
if(regex_match(str,pattern))
{ cout<<"Good!"; }
else cout<<"Try again";

Answer 2

To use the regex library, you need to ensure that your compiler supports c++11 (atleast). Try executing the following statement, and let me know what the output was :

cout<<__cplusplus<<endl;

Answer 3

Deep@Code i recommend using code::blocks instead of dev-c++, it's more up-to-standard

Answer 4

Dev C++ is giving me error while including the library #include <regex>

Answer 5

Output was 199711
@Kinshuk vasisht

Answer 6

Deep@Code That version is no good in 2018. You need to enable the flag '-std=c++11' for your compiler, or if possible, switch to Code::Blocks 17.12, as hinanawi mentioned.