Re: check Input

[Nafees via Digitalmars-d-learn]

On Monday, 17 April 2017 at 11:51:45 UTC, dennis wrote:

Hi,
try to build a little programm, but need to know
how to check the input.

For example:  input only numbers: 0 - 9 but 1.5 for example is 
ok.

thanks

How I would do it:
Run a loop, checking if the characters in input are within the 
range (i.e 0-9 and '.' character)
<code>
import std.stdio;
import std.conv : to;
import std.algorithm : canFind;

private bool isNum(string s){
        bool r=true;
        uinteger i;
        for (i=0;i<s.length;i++){
                if (!"0123456789.".canFind(s[i])){
                        r = false;
                        break;
                }
        }
        return r;
}

void main(){
        string input = readln;
        if (input.isNum){
                float f = to!float(input);
                if (f > 0 && f < 9){
                        writeln("Number is in range");
                }else{
                        writeln("Out of range");
                }
        }
}