Getting input as a char array?

[hibbijo]

I'm at a complete loss and don't really know where to begin.
But basically what I need to do is get a 4digit positive integer and filter out incorrect inputs.
Examples of correct inputs: 1234, 0000, etc.
Examples of incorrect inputs: 12, 12wf, etc.

Pseudo-code of what I'm trying to do:
Get the input and put it into an array.
Check the array to see if it's 4 characters long, if it's not display an error and get the input again.
Check the array to see if all 4 values stored are 0-9, if they aren't display an error and get the input again.

[roversoccer18]

Use a for loop from 0 to length of the array(in this case 3), and inside of the for loop you can just add one if state

if((typeof(arr[i])==int) && (arr[i]>=0)&&(arr[i]<10)}{

correct input
}
else{
incorrect input
}

[Mohamed Fouad]

This is very easy to do here this does it.

#include<iostream>
#include<cctype>

using namespace std;

bool doAgain();

int main()
{
	while(doAgain());
	cout << "Valid input.\n";
	return 0;
}

bool doAgain()
{
	char a[4];
	cout << "Enter a 4 digit number: " ;
	for(int i=0;i<4;i++)
	{
		cin >> a[i];
		if(!isdigit(a[i])) // checks if character by character is a digit or not.
		{
			cout << "Inputs contains non integer char.\n";
			cin.ignore(); //ignores the rest of the input.
			return 1;
		}
	}
	char x = cin.get();
	if(x!='\n') // if you find 1 more char available for input and that character is not the enter button.
	{
		cout << "Input contains more than 4 characters.\n";
		cin.ignore(); //ignores the rest of the characters in the input stream.
		return 1;
	}


	return 0;
}

[ascii]

mines shorter :)

#include <iostream>
#include <cctype>
#include <cstring>
using std::cout;
using std::cin;
using std::endl;

int main(void)
{
	const int max = 10;
	char string[max] = {0};
	cout << "Please enter 4 digits: " << endl;
	cin.getline(string, max, '\n');
		
	bool digits = true;
	for (int i = 0; i < strlen(string); i++)
	{
		if(!(isdigit(string[i])))
		{
			digits = false;
		}
	}

	while(!digits || strlen(string) < 4 || strlen(string) > 4)
	{
		cout << "Invalid input: " << endl;
		cin.getline(string, max, '\n');
	}	

	return 0;
}

[GodPyro]

Mine is shortest :D

#include <iostream>
#include <string>
#include <ctype.h>

using namespace std;

int main()
{
    string input = "";
    while (true) 
    {
        cout << "Please enter a 4 digit number: ";
        getline(cin, input);

        if(input.length() == 4)
            if(isdigit(input[0]) && isdigit(input[1]) && isdigit(input[2]) && isdigit(input[3]))
                break;
            
        cout << "Invalid input, please try again" << endl;
    }
    return 0;
}

[Mohamed Fouad]

I think he needs to get the input as a character array not a string that's why mine is longer.

[GodPyro]

A string is a character array. : /

[ascii]

except that strings suck more OOOOOOOOOOOOOOOOOOOOOOHHHH did i just say that???

[GodPyro]

What did the strings ever do to you, man?!

[Mohamed Fouad]

Yes stings are character arrays? Then why are there cstrings and why do we have this??
string str = "Hello.";
str.c_str(); ?????

[GodPyro]

The only difference between a character array and a string is that a string is a defined class with functions handling the use of the character array.
http://www.cplusplus.com/reference/string/string/

In memory it is the same thing.

[ascii]

lol i just find that character arrays are more useful if you need access to the individual characters of the string, which if youre getting user input you usually are...?

[Albatross]

ascii, you can access the individual characters of a C++ string the exact same way as you can with a char array, with []. But you knew that. :)

-Albatross

[GodPyro]

@Albatross Sweet. I had my suspicions but forgot to try. Thanks Albatross. :D

[ascii]

of course i knew that, it was a... test?