Language: C

k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'k' [-Wimplicit-int]
main.c:1:3: error: initialization of 'int' from 'char *' makes integer from pointer without a cast [-Wint-conversion]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |   ^~~~~~
main.c:1:3: error: initializer element is not computable at load time
main.c:1:22: error: initializer element is not constant
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                      ^
main.c:1:24: error: return type defaults to 'int' [-Wimplicit-int]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                        ^~~~
main.c: In function 'main':
main.c:1:37: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                                     ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
main.c:1:37: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                                     ^~~~~
main.c:1:37: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:43: error: passing argument 1 of 'scanf' makes pointer from integer without a cast [-Wint-conversion]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                                           ^
      |                                           |
      |                                           int
main.c:1:43: note: expected 'const char *' but argument is of type 'int'
main.c:1:72: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                                                                        ^~~~~~
main.c:1:72: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:72: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:1:72: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:79: error: passing argument 1 of 'printf' makes pointer from integer without a cast [-Wint-conversion]
    1 | k="%f\n";float a,y,x=k;main(){for(;~scanf(k,&a);y=a>y?a:y)x=a<x?a:x;a=!printf(k,y-x);}
      |                                                                               ^
      |                                                                               |
      |                                                                               int
main.c:1:79: note: expected 'const char *' but argument is of type 'int'