What s the Use of r escape sequence

Question

I have C code like this:

#include<stdio.h>
int main()
{
    printf("Hey this is my first hello world \r");
    return 0;
}

I conducted an experiment using the r escape sequence. 

I get the following output when I execute the code:

o world

Why is that, and what does r actually do?

If I use an online compiler to run the same code, I get the following results:

Hey this is my first hello world

Why did the online compiler ignore the \r and create different output?

Answer 1

The programme prints "Hey, this is my first hello world," then returns the cursor to the beginning of the line.

Your surroundings will determine how this appears on the screen.

Something looks to be overwriting the beginning of the string, maybe your command line prompt.