C++

NothingElseMatters · 05-28-2013, 01:48 PM

#include<iostream.h>
int main ()
{
int a,b,c,D;
double x1,x2;
cin>>a>>b>>c;
if (a!=0)
{
D=b^2-4*a*c;
if (D>0)
{
x1=(-b+sqrt(D) )/(2*a);
x2=(-b-sqrt(D) )/(2*a);
cout<<x1<<x2;
}
else
if (D=0)
{
x1=-b/(2*a);
cout<<"solutie dubla",x1;
}
else
cout<<"Nu are solutii reale";
}
else
cout<<"Nu este ecuatie de gr II ";
return 0;
}

EcgrII.cpp:12: error: `sqrt' was not declared in this scope

please help me ..what is wrong?

jdkaye · 05-28-2013, 02:09 PM

Are you missing this?

Code:

#include <math.h>

jdk

Tinkster · 05-28-2013, 03:03 PM

Moved: This thread is more suitable in <PROGRAMMING> and has been moved accordingly to help your thread/question get the exposure it deserves.

dwhitney67 · 05-28-2013, 04:20 PM

Include <cmath>.

johnsfine · 05-28-2013, 04:29 PM

Quote:

Originally Posted by dwhitney67

Include <cmath>.

I think cmath gives you std::sqrt, rather than sqrt in global scope.

I think that is the difference between math.h and cmath in C++

I don't mean to endorse the style of using math.h and using things like sqrt in global scope. I don't like that style. But the OP is using sqrt from global scope and thus needs sqrt in global scope.

With cmath (rather than math.h) the correct using statement could put the desired things into scope. So you can use cmath and still abuse global scope. I'm just saying the include of cmath isn't enough.

dwhitney67 · 05-28-2013, 06:27 PM

Quote:

Originally Posted by johnsfine

I'm just saying the include of cmath isn't enough.

Agreed; this is something I learned about 14 years ago. I figured the OP was referencing an up-to-date tutorial/book, but after revisiting his posted code, I realized he is not.

@ the OP -- Consider using the following:

Code:

#include <iostream>     // not iostream.h
#include <cmath>

use std::cout;
use std::endl;
use std::sqrt;

int main()
{
    ...
};

P.S. Take care in reading raw input from a user. There's no guarantee that a user will enter 3 int values.

P.S. #2 Using a 'return 0' at then end of the main() function is superfluous. C++ programs, when exiting gracefully, automatically return zero as the exit status.