c-gcc, 69 bytes

Result

AC

Code [DL]

#include<string.h>
s[1];main(){qsort(gets(s),100,1,strcmp);puts(s);}

stdin

4114395886624114009835906119248650608266987951116262217322339120196234178024153521449388348664894835

stdout

0000000111111111111111222222222222333333333344444444444455555556666666666667778888888888889999999999

stderr

/volume/CODE.c:2:1: warning: data definition has no type or storage class
 s[1];main(){qsort(gets(s),100,1,strcmp);puts(s);}
 ^
/volume/CODE.c:2:1: warning: type defaults to ‘int’ in declaration of ‘s’ [-Wimplicit-int]
/volume/CODE.c:2:6: warning: return type defaults to ‘int’ [-Wimplicit-int]
 s[1];main(){qsort(gets(s),100,1,strcmp);puts(s);}
      ^
/volume/CODE.c: In function ‘main’:
/volume/CODE.c:2:13: warning: implicit declaration of function ‘qsort’ [-Wimplicit-function-declaration]
 s[1];main(){qsort(gets(s),100,1,strcmp);puts(s);}
             ^
/volume/CODE.c:2:19: warning: implicit declaration of function ‘gets’ [-Wimplicit-function-declaration]
 s[1];main(){qsort(gets(s),100,1,strcmp);puts(s);}
                   ^
/volume/CODE.c:2:41: warning: implicit declaration of function ‘puts’ [-Wimplicit-function-declaration]
 s[1];main(){qsort(gets(s),100,1,strcmp);puts(s);}
                                         ^
/tmp/cct0nN7J.o: In function `main':
CODE.c:(.text.startup+0xc): warning: the `gets' function is dangerous and should not be used.

strace