Warning: initialization makes pointer from integer without a cast in C

Question

I am getting the warning: initialization makes pointer from integer without a cast in C. What is a cast? What should I do?

void UpdateElement(Console* console)
{
    DynamicVector* CostList=getAllCosts(console->ctrl);
    int i,n;
    printf("Give the position of the element you want to delete:");
    scanf("%d",&n);
    for(i=n-1;i<getLen(CostList);i++)
    {
        Cost* c=(Cost*)getElementAtPosition(CostList,i);
        Cost* c2=AddCost(console); **//here I get the warning**
        update_an_element(console->ctrl,c,c2,i);
    }
}

Console* initConsole(Controller* ctrl)
{
    Console* console=(Console*)malloc(sizeof(Console));
    console->ctrl=ctrl;
    return console;
}

int createCost(Controller* ctrl, char* day, char* type, int sum)
{
    Cost* c=initCost(day,type,sum);
    save(ctrl->repo,c);
    return c; **//now here I get the warning**

}

Are there prototypes for all functions used within UpdateElement()? Or are they all defined beforehand? If not then an implicit declaration will be generated, that returns an int. — hmjd
– hmjd, Commented Mar 17, 2013 at 18:56
YOu don't need to cast the return value of malloc in a C program. — Carl Norum
– Carl Norum, Commented Mar 17, 2013 at 18:56
Could you post the declaration of the AddCost(…) function ? Seems it returns an int. You make it a pointer. That could be bad. See my answer. — Jean
– Jean, Commented Mar 17, 2013 at 18:58
@CucerzanRares: Maybe you should first write a question with all needed information instead of editing it every minute. — flyingOwl
– flyingOwl, Commented Mar 17, 2013 at 19:03

A4L · Accepted Answer · 2013-03-17 19:00:44Z

1

c is of type Cost* and the function createCost returns int. both are not compatible that's why the compiler complains about a missing cast, but you don't want to cast in this case.

Change the return type of that function to Cost*

answered Mar 17, 2013 at 19:00

A4L

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Comments

flyingOwl · Accepted Answer · 2013-03-17 19:08:05Z

1

I believe that:

AddCost(console);

is returning an integer which is then casted to a pointer (what the warning said).

edited Mar 17, 2013 at 19:08

answered Mar 17, 2013 at 18:59

flyingOwl

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2 Comments

Cucerzan Rares Over a year ago

AddCost returns because all the functions were void and I couldn't do Cost* c2-function() so I made AddCosts return.

flyingOwl Over a year ago

When AddCost() returns an integer then you know where and why there is a warning.

me me · Accepted Answer · 2013-12-08 23:31:16Z

1

C/C++ assumes the return type is an integer unless specified by a header or it's declaration. You probably called a function that wasn't declared beforehand in the program and didn't have a header. It assumed it was an int and gave you an error.

answered Dec 8, 2013 at 23:31

me me

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Comments

Jean · Accepted Answer · 2013-03-17 19:06:08Z

0

You may need to use

Cost* c2=(Cost*)AddCost(console);

But it may be unsafe since AddCost(...) is returning an other type.

As for the function

int createCost(Controller* ctrl, char* day, char* type, int sum)

It should be declared as

Cost* createCost(Controller* ctrl, char* day, char* type, int sum)

Why is it declared as int ?

edited Mar 17, 2013 at 19:06

answered Mar 17, 2013 at 18:56

Jean

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5 Comments

Cucerzan Rares Over a year ago

It worked there. Now I am getting the warning in controller. I edited the post with the code.

Jean Over a year ago

@CucerzanRares Then you need return (int)c; but your program will probably crash. The function should probably be declared as Cost* createCost(…).

flyingOwl Over a year ago

In which way is the call of AddCost(console) connected to the function createCost()?

Jean Over a year ago

@flyingOwl It is not really connected. There are two distinct warnings. One because the return type of createCost(…) is int where, apparently, it should be Cost*. One because it seems that the return type of AddCost(…) is int and the OP assigns (cast) it to a pointer of type Cost*. The only connection between the two is that the both involve an improper conversion from int to Cost* and vice versa.

flyingOwl Over a year ago

You're right, the OP has mixed up a lot casts and return types. I just wanted to add what I said above :)

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