Language: C

b,d,e,m;main(a){
	for(;d=!scanf("%d",&a),a;printf("%d\n",m))
		for(m=s;(e=d*d*d-a)<1;d++)
				b=sqrt(-e),m=fmin(d+b-e-b*b,m);
}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | b,d,e,m;main(a){
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'b' [-Wimplicit-int]
main.c:1:3: error: type defaults to 'int' in declaration of 'd' [-Wimplicit-int]
    1 | b,d,e,m;main(a){
      |   ^
main.c:1:5: error: type defaults to 'int' in declaration of 'e' [-Wimplicit-int]
    1 | b,d,e,m;main(a){
      |     ^
main.c:1:7: error: type defaults to 'int' in declaration of 'm' [-Wimplicit-int]
    1 | b,d,e,m;main(a){
      |       ^
main.c:1:9: error: return type defaults to 'int' [-Wimplicit-int]
    1 | b,d,e,m;main(a){
      |         ^~~~
main.c: In function 'main':
main.c:1:9: error: type of 'a' defaults to 'int' [-Wimplicit-int]
main.c:2:17: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    2 |         for(;d=!scanf("%d",&a),a;printf("%d\n",m))
      |                 ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | b,d,e,m;main(a){
main.c:2:17: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    2 |         for(;d=!scanf("%d",&a),a;printf("%d\n",m))
      |                 ^~~~~
main.c:2:17: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:2:34: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    2 |         for(;d=!scanf("%d",&a),a;printf("%d\n",m))
      |                                  ^~~~~~
main.c:2:34: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:2:34: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:2:34: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:3:23: error: 's' undeclared (first use in this function)
    3 |                 for(m=s;(e=d*d*d-a)<1;d++)
      |                       ^
main.c:3:23: note: each undeclared identifier is reported only once for each function it appears in
main.c:4:35: error: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
    4 |                                 b=sqrt(-e),m=fmin(d+b-e-b*b,m);
      |                                   ^~~~
main.c:1:1: note: include '<math.h>' or provide a declaration of 'sqrt'
  +++ |+#include <math.h>
    1 | b,d,e,m;main(a){
main.c:4:35: warning: incompatible implicit declaration of built-in function 'sqrt' [-Wbuiltin-declaration-mismatch]
    4 |                                 b=sqrt(-e),m=fmin(d+b-e-b*b,m);
      |                                   ^~~~
main.c:4:35: note: include '<math.h>' or provide a declaration of 'sqrt'
main.c:4:46: error: implicit declaration of function 'fmin' [-Wimplicit-function-declaration]
    4 |                                 b=sqrt(-e),m=fmin(d+b-e-b*b,m);
      |                                              ^~~~
main.c:4:46: note: include '<math.h>' or provide a declaration of 'fmin'
main.c:4:46: warning: incompatible implicit declaration of built-in function 'fmin' [-Wbuiltin-declaration-mismatch]
main.c:4:46: note: include '<math.h>' or provide a declaration of 'fmin'