Language: C

a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
main.c:1:7: error: return type defaults to 'int' [-Wimplicit-int]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |       ^~~~
main.c: In function 'main':
main.c:1:21: error: 'i' undeclared (first use in this function)
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                     ^
main.c:1:21: note: each undeclared identifier is reported only once for each function it appears in
main.c:1:27: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                           ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
main.c:1:27: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                           ^~~~~
main.c:1:27: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:45: error: implicit declaration of function 'sort' [-Wimplicit-function-declaration]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                                             ^~~~
main.c:1:62: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                                                              ^~~~~~
main.c:1:62: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:62: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:1:62: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:98: error: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                                                                                                  ^~~~
main.c:1:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
  +++ |+#include <stdlib.h>
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
main.c:1:98: warning: incompatible implicit declaration of built-in function 'exit' [-Wbuiltin-declaration-mismatch]
    1 | a[10];main(){for(;++i<10;)scanf("%d",&a[i]);sort(&a[0],a[9]);printf("%d\n%d\n%d",a[9],a[8],a[7]);exit(0);}
      |                                                                                                  ^~~~
main.c:1:98: note: include '<stdlib.h>' or provide a declaration of 'exit'