sprintf has effect on serial.println()?

Projects Programming
1

Dear community,

I do not understand why the following code prints out:
&error = 200

int httpsCheck = 200;
char faultCode[30];

void setup() {
Serial.begin(74880);

}

void loop() {
sprintf(faultCode, "&error = %i", httpsCheck);
Serial.println(faultCode);
delay(1000);

}

There is no pointer used so how can Serial.println() print the whole char array?

Thank you.

Kind regards,

Niek

2

faultCode is a pointer.

3

Does printf covert the char array into a char*?

4

The name faultCode is a pointer.
It is equivalent to &faultCode [0]

5

the printf terminates the string with 0. the println prints the characters from array until the 0. that is C string

6

I thought char*text is the definition of a String in C and char text[] is a character array in C.

Does the println() function take in a pointer as parameter?

7

NiekBeijloos:
I thought char*text is the definition of a String in C and char[] is a character array in C.

no

8

In c and c++, an array name used without an index is automatically treated as a pointer.

9

What were you expecting the Serial,println() output to be, if not the text you put in faultcode with the sprintf command?

10

NiekBeijloos:
Does the println() function take in a pointer as parameter?

One of its overloaded versions does. Find Print.h in your Arduino installation. Inside you'll see:

size_t println(const char[]);

As has already been pointed out, the name of an array is treated as a pointer in function calls.

Edit:
So, the above is equivalent to:

size_t println(const char *);
11

NiekBeijloos:
I thought char*text is the definition of a String in C

The String class is C++, not C.

It has a capital S as a reminder and warning never to use it.