Why is onlineGDB not giving the same result as another compiler?

It is an online compiler and debugger for common programming languages such as C, C++, Python, Java, PHP, Ruby, Perl, and others

In this video, we will be exploring an Online GDB compiler for HTML and CSS This compiler is

onlinegdc Compile & run your code with the CodeChef online IDE Our online compiler supports multiple programming languages like Python, C++, C, JavaScript, Rust, Go,

onlinegdc Online GDB is online compiler and debugger for CC++ You can compile, run and debug code with gdb online Using gccg++ as compiler and gdb as debugger