Error printf was not declared in this scope

Table of Contents

What’s wrong with the following code? (Hint: there are two errors)

#include<iostream>
using namespace std;
 
int main(){
 
  int foo;
 
  for(int i = 0, i<100, i++) {
    foo++;
    cout << foo << endl;
  }
  return 0;
}

When compiled this yields:

junk.cpp:9: error: expected initializer before '<' token

junk.cpp:13: error: expected primary-expression before 'return‘

junk.cpp:13: error: expected `;' before 'return‘

junk.cpp:13: error: expected primary-expression before 'return‘

junk.cpp:13: error: expected `)' before 'return‘

First, the parameters of the for loop need to be separated by semicolons, not commas.

for(int i = 0; i<100; i++) {
    foo++;
    cout << foo << endl;
  }

Now look at this sample output of the corrected code:

-1208637327

-1208637326

-1208637325

-1208637324

-1208637323

-1208637322

Why the weird values? Because we never initialized foo before incrementing it.

 int foo = 0;

Two things to check here:

(1) Did you add

 #include<iostream> 

to your list of headers?
(2) Did you add

 using namespace std; 

after your #includes?

Add

 #include<cstdio> 

to your list of headers. Note if you are coming from C programming, adding
#include<cstdio> is preferred in C++ over #include <stdio.h>.

junk.cpp:8: warning: cannot pass objects of non-POD type 'struct std::string' through '…'; call will abort at runtime

junk.cpp:8: warning: format '%s' expects type 'char*', but argument 2 has type 'int‘

What this usually means is that you forgot to append .c_str() to the name of your string variable when using printf.

This error occurred when trying to compile the following code:

int main(){
 
  string foo = "dog";
  printf("This animal is a %s.n",foo);
  return 0;
}

Simply appending to .c_str() to “foo” will fix this:

printf("This animal is a %s.n",foo.c_str());

The reason you got this error is because printf is a C function and C handles strings differently than C++

junk.cpp:8: error: invalid use of member (did you forget the '&' ?)

What this usually means is that you forget to add () to the end of a function call.

Ironically, every time I see this it is never because I forgot the ‘&’.
This error occurred when trying to compile the following code:

int main(){
 
  string foo = "dog";
  printf("This animal is a %s.n",foo.c_str);
 
  return 0;
}

Simply adding the open and close parentheses () will take care of this for you:

printf("This animal is a %s.n",foo.c_str());

trycredit.cpp:86: error: request for member 'print' in 'card', which is of non-class type 'CreditCard*‘

What this usually means is that you are using a ‘.’ between the class pointer and the function you are trying to call.
Here is an example from the CreditCard lab:

void useCard(CreditCard *card, int method) {
  //Used to access the methods of the class
 
  if (method==1) {
    card.print();
  }

Since card is a CreditCard* we need → rather than . Fixed:

  if (method==1) {
    card->print();
  }

This error usually means you need to add a destructor to your myClass.cpp/myClass.inl code.
If you don’t want to implement a real destructor at this point, you can write something like this:

myClass::~myClass(){}

So long as the destructor exists, you should now be able to compile fine. Of course,
implement a real destructor at a later point.

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• error: ‘printf’ was not declared in this scope

1. error: ‘printf’ was not declared in this scope
   

   Hi,

   I want to try the code below and It is a code with preprocessors. I get an error.

   Can anyone can tell me the reason?

   Code:

   #define HATALI(A) A*A*A /* Kup icin hatali makro */
   #define KUP(A) (A)*(A)*(A) /* Dogusu ... */
   #define KARE(A) (A)*(A) /* Karesi icin dogru makro */
   #define START 1
   #define STOP 9
   
   main()
   {
   int i,offset;
   
   offset = 5;
   
   for (i = START;i <= STOP;i++) {
   printf("%3d in karesi %4d dir, ve kubu ise %6d dir..n",
   i+offset,KARE(i+offset),KUP(i+offset));
   
   printf("%3d in HATALIsi ise %6d dir.n",i+offset,HATALI(i+offset));
   }
   }

   the error:

   Code:

   'printf' was not declared in this scope

   ---

2. Re: error: ‘printf’ was not declared in this scope
   

   ---

3. Re: error: ‘printf’ was not declared in this scope
   

   WW ,
   Thanks for help

   when included the <studi> header file

   it returned an error:

   Code:

   studio.h: No such file or directory

   I am using gcc compiler. Can this be the reason?

   ---

4. Re: error: ‘printf’ was not declared in this scope
   

   ---

5. Re: error: ‘printf’ was not declared in this scope
   

   WW,thanks.
   I’m so inattentive

   anyway, the program give a more garbled error…

   what does this error mean?

   how can I fix the problem?

   Code:

   /tmp/ccGQNcoh.o:(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
   collect2: ld output returned 1

   ---

6. Re: error: ‘printf’ was not declared in this scope
   

   What command did you use that results in that error?

   ---

7. Re: error: ‘printf’ was not declared in this scope
   

   I’m using vi editor and first of all I created a file like this:

   Code:

   user@user-desktop:~$ vi example_macro.cpp

   then I compiled the file by the command:

   Code:

   sh-3.1$ gcc example_macro.cpp -o objmacro

   by the way I have a off topic question,
   I have created a file:

   user@user-desktop:~$ mkdir make_file_work

   then I go and look both the ‘user’ file and to the ‘desktop’ I cannot find such a directory? But if I write the command:

   user@user-desktop:~$ cd make_file_work

   I can go inside that file, but I cannot see it in the file browser…

   why?

   thanks again for your help WW…

   ---

8. Re: error: ‘printf’ was not declared in this scope
   

   You appear to be writing C, not C++. Rename the file to example_macro.c, and try again. (I just tried it both ways; I got the same error that you did when the file was called example_macro.cpp, and it compiled fine when I called it example_macro.c.)

   ---

9. Re: error: ‘printf’ was not declared in this scope
   

   It’ll compile as a .cpp if you put the line…

   Code:

   using namespace std;

   under the include for stdio.h, or preface printf with «std::» in order to tell the compiler that you’re using a function from the standard namespace.

   ---

10. Re: error: ‘printf’ was not declared in this scope
    

    Yes, it compiled when I changed the extesion from .cpp to .c. But I dont know the diferrences between the c and cpp.

    Does the reason depends to ‘printf’ function? Because, as far as I remember I use cout function instead of printf in cpp. I guess printf is a c function…

    But when I tried with
    #include <stdio>
    using namespace std;

    it gave an error again. the error the same:

    Code:

    /tmp/ccubDW3d.o:(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
    collect2: ld output return 1

    what does this error mean anyway?

    «/tmp/ccubDW3d.o» :……………………………………what is the object ccubDW3d.o in the ‘tmp’ directory?

    «(.eh_frame+0x11)» :………………………………….. can this be an address?

    «undefined reference to `__gxx_personality_v0′» : it says ‘__gxx_personality_v0’ and says there is an undefined reference to this ‘thing’. But I’ve not use that thing in my . ………………………………………….. …………………..code. What does it refer to in my code?
    «collect2: ld output return 1» : what is collect 2? What is ld output? What does returning 1 means?

    WW and Mime thanks for help

    Last edited by ankakusu; June 3rd, 2007 at 11:10 AM.

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