Check string for numbers

Question

I'm trying to write a function that checks if a string contains a number, positive or negative.

getline(cin,line);

    istringstream sin(line);

    while (sin >> ws >> in){

        if(all_of(in.begin(), in.end(), ::isdigit){
        //do something with number
        }

Problem is, isdigit() will set all negative numbers as not numbers. What other ways are there to check whether a string contains numbers?

Sample input: 1 2 -2 asdf 4.

Why don't you directly work on `line`, rather than wrapping a string stream round it? — Alan Stokes, Nov 16 '14 at 13:25

score 0 · Accepted Answer · answered Nov 16 '14 at 13:23

0

Check if the leading character is - (or +, or whatever else you'll accept), and if so, remove it, then use your current test for what remains.

A fuller solution would be to use a regular expression.

answered Nov 16 '14 at 13:23

Scott Hunter

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Check string for numbers

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