Thread: C++ String Question

Ok, basically I have a user inputted string named ssn, for entering social security numbers. I have the user input it with a getline function, but after that I need to test this string to make sure a 9 digit number was entered into it. How would I check this string to make sure all of the characters are numbers (0-9)?

None of the string functions I've used seem to work with this, and tend to have problems because the string values are characters.

Any help would be much appreciated, I honestly can't find help for this in either of my books.

Silverwolf

Thank you very much! I knew I was overlooking something. I really appreciate it.

Silverwolf

I would have tried something like

Code:

for(int a = 0; a < 7; a++)
{
if(number[a] != '0' || '1' || '2' ...

but that didn't work. I don't know what to tell you. You might have to say

Code:

if(number[a] == 'a')
{
//error
}

for every character. Something like

Code:

if(number[a] == 'a' || 'b' || 'c')
{
//error
}

doesn't work either on my compiler. Good luck.

Originally posted by Mr_Jack
I would have tried something like

Code:

for(int a = 0; a < 7; a++)
{
if(number[a] != '0' || '1' || '2' ...

but that didn't work. I don't know what to tell you.

Mr_Jack - I think joshdick was able to give a good solution to wolff76. Just for your knowledge, to do it the way you were trying to do it, you must explicitly type out "number[a] != " for each comparison. It doesn't work like in english where you can say "x does not equal 1 or 2 or 3". The correct statement is, "x does not equal 1 and x does not equal 2 and x does not equal 3."

Code:

for(int a = 0; a < number.length(); a++)
{
    if(number[a] != '0' && number[a] != '1' && number[a] != '2' ...)