Compiler Error in Solo Learn Code Playground "C" compiler

Question

Here is a simple C program

/* Numeric Data Type sizes in bytes */
#include <stdio.h>

int main()
{
printf("\n char is %d bytes", sizeof(char));
printf("\n unsigned char is %d bytes", sizeof(unsigned char));
printf("\n int is %d bytes", sizeof(int));
printf("\n unsigned int is %d bytes", sizeof(unsigned int));
printf("\n short is %d bytes", sizeof(short));
printf("\n unsigned short is %d bytes", sizeof(unsigned short));
printf("\n long is %d bytes", sizeof(long));
printf("\n unsigned long is %d bytes", sizeof(unsigned long));
printf("\n float is %d bytes", sizeof(float));
printf("\n double is %d bytes", sizeof(double));

return 0;
}

This code compiles correctly, without modification on my local machine.

However, when I compile it within Solo Learn's Code Playground it produces a "Compiler Error". I comment out the half of the printf's (doesn't matter which ones) the program compiles correctly.

For example:
#include <stdio.h>

int main()
{
/* printf("\n char is %d bytes", sizeof(char)); */
printf("\n unsigned char is %d bytes", sizeof(unsigned char));
printf("\n int is %d bytes", sizeof(int));
/* printf("\n unsigned int is %d bytes", sizeof(unsigned int)); */
/* printf("\n short is %d bytes", sizeof(short)); */
printf("\n unsigned short is %d bytes", sizeof(unsigned short));
/* printf("\n long is %d bytes", sizeof(long)); */
printf("\n unsigned long is %d bytes", sizeof(unsigned long));
/* printf("\n float is %d bytes", sizeof(float)); */
printf("\n double is %d bytes", sizeof(double));

return 0;
}

Anyone have similar problems, or care to verify the bug in the Code Playground compiler?

Answer 1

Well, this was an odd one. Here's a debugging trick....

You've got a lot of warnings, which you can see by commenting half your code lines and adding a nonsense/uncompilable function call like:
blah(); // stop compiler and show warnings up to this point

** The format code is complaining about %d expecting an integer while receiving "unsigned long long int".

On Linux platforms the proper format code is %llu, on Windows it's something like %I64u.
https://stackoverflow.com/questions/2844/how-do-you-printf-an-unsigned-long-long-intthe-format-specifier-for-unsigned-lo

This works here:
printf("\n char is %I64u bytes", sizeof(char));
printf("\n unsigned char is %I64u bytes", sizeof(unsigned char));
printf("\n int is %I64u bytes", sizeof(int));
....all of them

As for why it crashes with "Compilation error" (when warnings should maybe continue?)... probably too much warning text in the pipe... ? ...but I don't have visibility on that.
I'll send a copy to SoloLearn so they can evaluate it.

Answer 2

See Kirk Schafer's reply:
Nice one Kirk - your explanation makes perfect sense. Also, thanks for passing it on to the team at SL.

Answer 3

It's sent; and thanks for providing the equivalent of the smallest representative sample -- that makes analysis a lot easier.

Answer 4

maybe the internet connection.
since the code playground is server based, it could probably happen.