Square Root...

I have been trying to take the square root of a number by doing this:

Code:

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a = Sqr(25);

---

And

Code:

---

a = Sqrt(25);

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I get the following error:error C2065: 'Sqr' : undeclared identifier

and error C2065: 'Sqrt' : undeclared identifier....

What is wrong?

Include the math.h header file.

Code:

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#include <math.h>
...
double root = sqrt(nymber);

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It's in the math.h system header, and since it's a library function it's all lower case:

Code:

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float x = sqrt(5.4f);

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I'll let you have that one ;)

parksie 1 - 1 Vlatko

:D:D

Now I get the error:

C:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(41) : error C2361: initialization of 'x' is skipped by 'default' label
C:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(37) : see declaration of 'x'

What's at those lines?

Code:

---

switch(choice){
        case 1 :
                // Do actions
        break;
        case 2 :
                cout<<"Input a: ";
                cin>>a;

                cout<<""<<endl;

                cout<<"Input b: ";
                cin>>b;

                cout<<""<<endl;

                cout<<"Input c: ";
                cin>>c;

                d = b * b - 4 * a * c;
                cout<<d<<endl;
                double x = sqrt(d);
               
                l1 = -b - x / 2 * a;
                l2 = -b + x / 2 * a;
               
                cout<<""<<endl;
               
                cout<<"L1: " <<l1<<endl;
                cout<<"L2: " <<l2<<endl;
       
        break;
        default:
                cout<<"Choose either 1 or 2"<<endl;
        }

---

You'll need to put the definition for double x before the switch block.

Now I get the following error:

:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(16) : error C2086: 'x' : redefinition
C:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(40) : warning C4244: '=' : conversion from 'double' to 'float', possible loss of data
C:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(41) : warning C4244: '=' : conversion from 'double' to 'float', possible loss of data
C:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(49) : error C2361: initialization of 'x' is skipped by 'default' label
C:\Programmer\Microsoft Visual Studio\MyProjects\Equation\equation.cpp(37) : see declaration of 'x'

Code:

---

double x;
        switch(choice){
        case 1 :
                // Do actions
        break;
        case 2 :
                cout<<"Indtast a: ";
                cin>>a;

                cout<<""<<endl;

                cout<<"Indtast b: ";
                cin>>b;

                cout<<""<<endl;

                cout<<"Indtast c: ";
                cin>>c;

                d = b * b - 4 * a * c;
                cout<<d<<endl;
                double x = sqrt(d);
                cout<<x<<endl;

                l1 = -b - x / 2 * a;
                l2 = -b + x / 2 * a;
               
                cout<<""<<endl;
               
                cout<<"L1: " <<l1<<endl;
                cout<<"L2: " <<l2<<endl;
       
        break;
        default:
                cout<<"Choose either 1 or 2"<<endl;
        }

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Obviously you need to take out the second definition :rolleyes:

Try initialising it to 0 at the start, though.