help i cant get it working

i am new with c. i was using c++ before this. i dont get it why i cant get it to work with so many error. can someone show me the correct way.
i was wondering which is the best function to use in order to prom a error message when an invalid character is entered then go back to the scanf function to enter again.
thanks

One thing I noticed when opening in a syntax-highlighting text editor (SciTE)...some of your printfs have extra quotes.

Quote:

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Originally Posted by rags_to_riches

One thing I noticed when opening in a syntax-highlighting text editor (SciTE)...some of your printfs have extra quotes.

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He is right. Also i think you like to do

Code:

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    do
    {
      printf("enter option here: ");
      scanf("%d",&option);
      switch ( option )

---

instead of

Code:

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printf("enter option here: ");
        scanf("%d",&option);
        do
        {

        switch ( option )

---

When I compile your program using VC++ 6.0, I get 102 errors, not to mention the warnings. Your #define statements won't cut the mustard. Just remove the #define and that should take care of all those errors and warnings. You also will have to remove the '+' and '-' signs. Maybe define as "char APlus[2]", etc.

Also "Score * 3 = english_language;" is backwards --- "english_language = Score * 3;"

That should get you started. You have other errors to fix as well.

Way to many warnings/errors with this. Also what is your intent on:

Code:

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while( option > 3 || option < 3 );

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Your options for your switch are for 1,2,3.

Also your function grade_value() is not declaried. Your only function outside of main() is

Code:

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double Grade ( char &Grade )

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Again, your scanf() is expecting a %s, string, yet you are assigning to &Grade which is of type char. This gives only a warning, but is not clean code.

Have you compiled this and have seen these warning and errors yourself?

As already mentiond your #defines are causing most of your troubles, which gives syntax errors with the use of '['.

ive taken you guy's advice thanks alot. and this is an revised version of the program. but i still have errors. can anyone help me with it. i still can't figure out how to solve it. thanks. if possible correct the source code and post it up. thanks alot.

Remove all those defines.

Code:

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//#define char f;

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Local function definitions are illegal (INDENT PROPERLY and you wouldn't have this problem!):

Code:

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void Sem_1 ( void )

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Void is not necessary for inside argument lists in C++ (which is what you're compiling it as):

Code:

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void Sem_1 ()

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Due your indentation problem, the code is all in the wrong places because you missed a }:

Code:

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        do
        {

                printf("enter option here: ");
                scanf("%d",&option);
                switch ( option )
                {
                case 1:

                        system ( "cls" );
                        Sem_1();

                        break;

                case 2:

                        system ( "cls" );
                        Sem_2();

                        break;

                case 3:

                        system ( "cls" );
                        Sem_3();

                        break;
                }
        }
        while( option > 4 || option < 4 );
        return 0;
}

---

Missing ;

Code:

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int back_1;

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writing_for_mass_communication: undeclared variable.

Code:

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writing_for_mass_communication = Score * 3;

---

Code:

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Score * 3 = computer_studies;

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Perhaps you intended:

Code:

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computer_studies = Score * 3;

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Missing ;

Code:

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printf("press 0 to go back to option menu");

---

Code:

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scanf("%d", &back_1);

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computer_studies: undeclared variable.

Code:

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computer_studies = Score * 3;

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gpa_sem_1: undeclared variable.

Code:

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cgpa_sem_2 = ( ( gpa_sem_1 + gpa_sem_2 ) / 2 );

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Missing ;

Code:

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printf("press 0 to go back to option menu");
scanf("%d", &back_2);

---

gpa_sem_1, gpa_sem_2: undeclared variables.

Code:

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cgpa_sem_3 = ( ( gpa_sem_1 + gpa_sem_2 + gpa_sem_3 ) / 3 );

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Missing ;

Code:

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printf("press 0 to go back to option menu")
scanf("%d", &back_3)

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Completely wrong in all sorts of ways and expectations.

Code:

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        if (strcmp( Grade, A+ || a+ == 0 ))
        {
                Score += 4.00;
        }
        else if (strcmp( Grade, A- || a- == 0 ))
        {
                Score += 3.70;
        }
        else if (strcmp( Grade, B+ || b+ == 0 ))
        {
                Score += 3.30;
        }
        else if (strcmp( Grade, B || b == 0 ))
        {
                Score += 3.00;
        }
        else if (strcmp( Grade, B- || b- == 0))
        {
                Score += 2.70;
        }
        else if (strcmp( Grade, C+ || c+ == 0 ))
        {
                Score += 2.30;
        }
        else if (strcmp( Grade, C || c == 0 ))
        {
                Score += 2.00;
        }
        else if (strcmp( Grade, D || d == 0 ))
        {
                Score += 1.00;
        }
        else if (strcmp( Grade, F || f == 0 ))
        {
                Score += 0.00;
        }
        else
        {
                printf( "invalid grade\n" );
                printf( "please enter again: " );
        }

---

Score: undeclared variable.

Code:

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Score += 4.00;

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Uninitialized variables public_speaking and writing_for_mass_communication used.

Code:

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gpa_sem_1 = ( ( english_language + public_speaking + principles_of_accounting +
principles_of_economics + general_mathematics_1 + computer_studies ) / 18 );

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You obviously know nothing about C or C++. Go back to school. This isn't a playground.
Make a real effort in making a program and start of small. When you've mastered the basics, come back and we'll help you.

how do i solve the three unresolced external symbols. i know it has got to do i with the function calling. but not sure how to solve it.
any advice on what logic should i use to do error warnings and go back to the previous data entry.
i am feeling the error is from this part but i am not sure what is it trying to point out.

//function prototype
double sem_1 ( void );
double sem_2 ( double );
double sem_3 ( double, double );

thanks for you help.

If you post WHICH symbols are unresolved, then that would help us quite a bit.

--
Mats

Why your c file has cpp extention? cpp is for C++, C-file in general have to have c-extention

C code can be compiled as C++ code, and to be honest, I would recommend it that way.

Quote:

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Originally Posted by Elysia

C code can be compiled as C++ code, and to be honest, I would recommend it that way.

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I wouldn't. If you want to write C++ - do it. If you are using C - use it. Do not mix 2 different languages in one compilation unit

But if i have C code i need to use in C++, would the recommended way be linking the object files to a library and #including their interface? When i inline functions in C header files, either as #define Macros or using the inline directive, then there are issues i should care for? I have not used C++ that much, but am not a total stranger, and i would like to know what is the best way to make both happy.

Quote:

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Originally Posted by Elysia

C code can be compiled as C++ code

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That's not entirely true, this is legal C code, but it won't compile on a C++ compiler for obvious reasons:

Code:

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int class = 0;

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This ofcourse applies to all keywords in C++ that C doesn't have. Also, why would you recommend a C++ compiler for C code?

C++ has a stronger type-checking than C, so that would be one reason to compile code with C++ compiler even tho' the code itself is C.

--
Mats

Quote:

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Originally Posted by matsp

C++ has a stronger type-checking than C, so that would be one reason to compile code with C++ compiler even tho' the code itself is C.

--
Mats

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Or rather not to - because you will need to fix all malloc calls adding casting to them... And so on...

Quote:

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Originally Posted by vart

Or rather not to - because you will need to fix all malloc calls adding casting to them... And so on...

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Yes, that would be one consequence of using C++ to compile C code. Again, I'm not saying anyone should, or shouldn't use the C++ compiler to compile C, just regurgitating someone else's reasoning for doing so. It's really up to the individual (or technical leader if you work for a company, perhaps).

--
Mats

Quote:

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Originally Posted by Neo1

That's not entirely true, this is legal C code, but it won't compile on a C++ compiler for obvious reasons:

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No, it won't compile without a few modifications, but it can compile. I never mentioned it will compile as-is.

Quote:

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Originally Posted by Neo1

This ofcourse applies to all keywords in C++ that C doesn't have. Also, why would you recommend a C++ compiler for C code?

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Four big reasons:
No implicit function calls allowed.
No missing return types of functions or arguments allowed.
C++ compilers are often more conforming than C compilers. For example, assigning one type to a variable of another type is not allowed without an explicit cast, both in C and C++, yet most C compilers allow it with merely a warning.
More type-safe.

These are the only reasons needed to prefer compiling C code as C++ code. There are further advantages to C++, as well, and probably further advantages to compiling as C++ code, but this is more than enough.
In the end, it will work exactly like the code was compiled in a C compiler, so no harm comes from doing it.

And as far as casting malloc goes, that's really irrelevant. The only reason you shouldn't cast it is because it will hide an implicit call (or supress the warning). In C++, implicit function calls are not allowed, so you can't make that mistake.

This is my view on the whole, anyway.