c-gcc, 81 bytes

Result

WA

Code [DL]

f(int*a){return*a-*1[&a];}char s[100];main(){gets(s);qsort(s,100,1,f);puts(s);}

stdin

4675321740850434588807128056755553847267977112707083495284221000895619766847226622996809851936808979

stdout

4675321740850434588807128056755553847267977112707083495284221000895619766847226622996809851936808979

stderr

/volume/CODE.c:1:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
 f(int*a){return*a-*1[&a];}char s[100];main(){gets(s);qsort(s,100,1,f);puts(s);}
 ^
/volume/CODE.c:1:39: warning: return type defaults to ‘int’ [-Wimplicit-int]
 f(int*a){return*a-*1[&a];}char s[100];main(){gets(s);qsort(s,100,1,f);puts(s);}
                                       ^
/volume/CODE.c: In function ‘main’:
/volume/CODE.c:1:46: warning: implicit declaration of function ‘gets’ [-Wimplicit-function-declaration]
 f(int*a){return*a-*1[&a];}char s[100];main(){gets(s);qsort(s,100,1,f);puts(s);}
                                              ^
/volume/CODE.c:1:54: warning: implicit declaration of function ‘qsort’ [-Wimplicit-function-declaration]
 f(int*a){return*a-*1[&a];}char s[100];main(){gets(s);qsort(s,100,1,f);puts(s);}
                                                      ^
/volume/CODE.c:1:71: warning: implicit declaration of function ‘puts’ [-Wimplicit-function-declaration]
 f(int*a){return*a-*1[&a];}char s[100];main(){gets(s);qsort(s,100,1,f);puts(s);}
                                                                       ^
/tmp/cc3ivvN3.o: In function `main':
CODE.c:(.text.startup+0xc): warning: the `gets' function is dangerous and should not be used.

strace