Thread: Pointer doubt

No, because result is an int now and does not need to be dereferenced. In this case you should just use result with out '*'. However, there will be no change to the variable back in main, once your function ends all arithmetic on variables will be useless without the presence of some pointers. It depends on your program whether or not a function like that will suffice.

>> So do you think it will be more eficient if i use:
No I don't think it would be more efficient.

But I do think you should know independently if your usage of pointers is ok or not. You will have to master them.

I don't need to update variable to main since this is a game with 4 stages, i just need to count the result, questions, wrong questions, etc

I'm keeping the pointers like this:

Code:

int gp3_Ques(char *usr1, int *result,int *total_perg,int *certas,int *erradas, int num[], int n)

since i call this function like this

Code:

gp3_Ques(usr1, &result, &total_perg, &certas, &erradas);

So if i understand, when i call the function i'm using & with memory adress, then i use in function prototype * to deferencing the variables, right?

Originally Posted by Gil Carvalho

The order is important??

Of course it is important!
Seriously, have you ever worked through a tutorial/book? Because I have the impression you don't understand some very fundamental programming concepts.

Iv'e changed to

Code:

int gp3_Ques(char *usr1, int *result,int *total_perg,int *certas,int *erradas, int num[], int n)

And how do you call this new function? Do you still call it without values for "num[]" and "n"?

BTW: Doesn't your compiler tell you about the missing arguments?

Bye, Andreas

No Andreas

"num[]" and "n"? are used

if ( jogo1Gp3(num,n) ) this call another function who randomize an array. (is working)

Hi Cristop

My code is this one

Code:

gp3_Ques(usr1, &result, &total_perg, &certas, &erradas);

Code:

int gp3_Ques(char *usr1, int *result,int *total_perg,int *certas,int *erradas, int num[], int n)
{


    system("cls");


    printf ("\n*=============================================================================*\n");
    printf ("|                           >>>>Ordenacao numeral<<<<                            |\n");
    printf ("*=============================================================================*\n");
    printf ("                                                                               \n");
    printf ("\n      Esta no bom caminho %s \n",usr1);
    printf ("\n      Traz da outra fase: %d pontos \n", result); //conta as perguntas
    printf ("\n      O seu score maximo sera: 2 \n"); //pontuação máxima do jogo
    printf ("                                                                               \n");
    printf ("*=============================================================================*\n");
    Sleep(3000);
    if ( jogo1Gp3(num,n) )
            {
                printf("\nAcertou na resposta...\n");
                result++;//incrementa a variavel result
                total_perg++;
                certas++;
                printf("Atencao a proxima pergunta...\n");
                Sleep(2000);
                if ( jogo1Gp3(num,n))
                {
                    printf("\nAcertou novamente na resposta...\n");
                    result++; //incrementa a variavel result
                    total_perg++;
                    certas++;
                }
                else
                {
                    printf("Resposta errada.... :(");
                    total_perg++;
                    erradas++;
                    Sleep(2000);
                    system("cls");
                }
            }
            else
            {
                printf("\nResposta errada....foi eliminado :(");
                total_perg++;
                erradas++;
                Sleep(2000);
                system("cls");
                jogo();
            }
    if (result>=7)
    {
        printf ("\n*=============================================================================*\n");
        printf ("|                       >>>>Resultado desta fase 3<<<<                        |\n");
        printf ("*=============================================================================*\n");
        printf ("                                                                               \n");
        printf("\nTem um total de %d pontos\n", result);
        printf("\nTem um total de %d perguntas\n", total_perg);
        printf("\nTem %d de respostas certas.\n", certas);
        printf("\nTem %d de respostas erradas.\n", erradas);
        printf("\n                        Vai passar para a fase 4...aguarde \n");
        printf ("*=============================================================================*\n");
        Sleep(5000);
        //gp3_Ques(usr1, &result);
    }
    else
    {
        printf("Nao atingiu o minimo para seguir....vai voltar ao menu anterior");
        Sleep(2000);
        system("cls");
        jogo();
    }
    return 0;
}

All the warnings are when i want to print a variable

warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|

I have already tried several ways...

>> warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|

Right, so you want to print an integer. Pointer p points to an integer. What expression involving p did you learn that is of type integer?

... *p
So use that information. I was hoping you would learn it, but I just wound up disappointed in myself.

Is this the current prototype for gp2_Ques?

Code:

int gp2_Ques(struct gp2 *p, char *usr1, int *result,int *total_perg,int *certas,int *erradas);

If so, what type is the expression &result?

It's not a pointer to int. It's a pointer to a pointer to int (int **). So you're passing the wrong thing to gp3_Ques.

Again, turn on your compiler warnings, and pay attention to them. I'm pretty sure your compiler warns you that you're passing an int ** to the function gp3_Ques where an int * is expected.

Sorry christop

my current prototype is

Code:

 gp3_Ques(usr1, &result, &total_perg, &certas, &erradas);

Compiler warnings



D:\2012\c_exe\Projeto Final\funcoes.c|901|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|939|warning: comparison between pointer and integer [enabled by default]|
D:\2012\c_exe\Projeto Final\funcoes.c|945|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|946|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|947|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|948|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
||Warning: resolving _Sleep by linking to _Sleep@4|
||=== Build finished: 0 errors, 6 warnings ===|

Originally Posted by Gil Carvalho

my current prototype is

Code:

 gp3_Ques(usr1, &result, &total_perg, &certas, &erradas);

That's not a prototype, that's a function call.

Bye, Andreas

Well, i think is better to put all my functions and prototypes.
Maybe there is something wrong

Code:

int gp1_Ques(struct perg *p, char *usr1)
//function call
gp2_Ques(&p, usr1, &result, &total_perg, &certas, &erradas);

//function2
int gp2_Ques(struct gp2 *p, char *usr1, int *result,int *total_perg,int *certas,int *erradas)

//Function call
gp3_Ques(usr1, &result, &total_perg, &certas, &erradas);


//Fucntion 3
int gp3_Ques(char *usr1, int *result,int *total_perg,int *certas,int *erradas, int num[], int n)

I feel that all of you thinks that i'm dummie but my doubt is why with function 2 i use printf *result, and i can't use in function 3 the same.

Code:

int gp1_Ques(struct perg *p, char *usr1)
//function call
gp2_Ques(&p, usr1, &result, &total_perg, &certas, &erradas);

//function2
int gp2_Ques(struct gp2 *p, char *usr1, int *result,int *total_perg,int *certas,int *erradas)

p is a pointer to struct perg. Then you call gp2_Ques with &p (which is now a pointer to a pointer to struct perg) but gp2_Ques needs a pointer to struct gp2.

Code:

//function2
int gp2_Ques(struct gp2 *p, char *usr1, int *result,int *total_perg,int *certas,int *erradas)

//Function call
gp3_Ques(usr1, &result, &total_perg, &certas, &erradas);

//Fucntion 3
int gp3_Ques(char *usr1, int *result,int *total_perg,int *certas,int *erradas, int num[], int n)

Here you have the same problem as above. result, total_perg, certas, erradas are already pointers to int. But with your call to gp3_Ques you make pointers to pointers. And you don't call gp3_Ques with values for num[] and n. So you should get an error from the compiler:

Code:

$ cat test.c
#include <stdio.h>

void f(int a, int b)
{
    printf("%d %d\n", a, b);
}

int main(void)
{
    f(1);

    return 0;
} 
$ gcc -Wall -o test test.c
test.c: In function ‘main’:
test.c:10:5: error: too few arguments to function ‘f’
test.c:3:6: note: declared here

Ok, thanks

Iv'e made some changes like you told me.

Code:

intgp1_Ques(structperg *p, char*usr1)
//function call
gp2_Ques(usr1, &result, &total_perg, &certas, &erradas);

//Function
int gp2_Ques(struct gp2 *p, char *usr1, int *result,int *total_perg,int *certas,int *erradas)

//function call
gp3_Ques(usr1, result, total_perg, certas, erradas);

//Function
int gp3_Ques(char *usr1, int *result,int *total_perg,int *certas,int *erradas)

Now between function 1 and 2 i don't have user , but i can't take it out, it's no necessary

D:\2012\c_exe\Projeto Final\funcoes.c||In function 'gp3_Ques':|
D:\2012\c_exe\Projeto Final\funcoes.c|938|warning: comparison between pointer and integer [enabled by default]|
D:\2012\c_exe\Projeto Final\funcoes.c|944|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|945|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|946|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
D:\2012\c_exe\Projeto Final\funcoes.c|947|warning: format '%d' expects argument of type 'int', but argument 2 has type 'int *' [-Wformat]|
||Warning: resolving _Sleep by linking to _Sleep@4|
||=== Build finished: 0 errors, 5 warnings ===|