C++ errors help

the code is this:

Code:

---

#include <stdio.h>
#include <math.h>

int main ()
{
    int a, b, r1, r2;
   
    printf("type in the 2 roots:");
    scanf("%d%d" &a, &b);
    r1 = a+b;
    r2 = a*b;
    printf("the equation in general form is: x*x+(%f)x+(%f)"r1, r2;
    system ("pause");
    return 0;
}

---

why doesn't it work?

Because you don't have a comma between your close quotation and r1, or between the close quote and &a.

thanks
i smash my head in the table when hearing this

another new problem occurs.....

Code:

---

#include <stdio.h>
#include <math.h>

int main ()
{
    int a, b, r1, r2;
   
    printf("type in the 2 roots:");
    scanf("%d%d", &a, &b);
    r1 = a+b;
    r2 = a*b;
    printf("the equation in general form is: x*x+(%f)x+(%f)", r1, r2);
   
    system("pause");
    return 0;
}

---

the program says that there is error in those red words i labelled
how come there is a mistake?

Probably you missed the header for the system function.

It always helps to post exactly what your compiler was complaining about, so people don't have to copy/paste your code into their compiler again, to get the same message you already knew about.

You should not be using scanf in the first place, or printf, unless you are actually doing C instead of C++ (whose section you have posted in)?

it's C++

First of all compiling your this code with g++ doesn't mean it c++ what features of c++ you are using in it...

well the errors are

Code:

---

#include <stdio.h>
#include <math.h>
#include <windows.h> // include this file on ms windows for system API call

int main ()
{
    int a, b, r1, r2;
   
    printf("type in the 2 roots:");
    scanf_s("%d %d", &a, &b); // , coma was missing
    r1 = a+b;
    r2 = a*b;
    printf("the equation in general form is: x*x+(%f)x+(%f)",r1, r2); // ) brace and , was missing
    system ("pause");
    return 0;
}

---

Actually, <cstdlib> is the correct header for std::system. Or if you prefer to use the C header, it would be <stdlib.h>.

By the way, please do not change the code to use the non-standard scanf_s, at least not without explaining very clearly the ramifications of such a change.

Quote:

---

Originally Posted by laserlight

Actually, <cstdlib> is the correct header for std::system. Or if you prefer to use the C header, it would be <stdlib.h>.

By the way, please do not change the code to use the non-standard scanf_s, at least not without explaining very clearly the ramifications of such a change.

---

About header file u are correct that can be done also



And about scanf_s on microsoft see this

Quote:

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warning C4996: 'scanf' was declared deprecated
C:\Program Files\Microsoft Visual Studio 8\VC\include\stdio.h(295) : see declaration of 'scanf'
Message: 'This function or variable may be unsafe. Consider using scanf_s instead. To disable deprecation, use _CRT_SECURE_NO_DEPRECATE. See online help for details.'

---

Quote:

---

Originally Posted by RockyMarrone

And about scanf_s on microsoft see this

---

It would be more helpful to mkmk007 if you actually linked to the MSDN article.

But my point is that you need to explain, not just make the change. Yes, when used incorrectly scanf is unsafe, but here its usage is fine, other than being a little odd in a C++ program. However, even if the usage of scanf was insecure, by making that change, you can cause the program to fail to compile, because scanf_s is not guaranteed to be present. This is an important ramification to consider. It should also be considered that Microsoft's _s versions of various standard library functions are more of a safety net than an actual improvement in security since they detect problems at run time rather than pre-empt them.

Thanks guys.....
the problem is solved