Language: C

#define p printf("
main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}

Compiler output:
main.c:1:18: warning: missing terminating " character
    1 | #define p printf("
      |                  ^
main.c:2:1: error: return type defaults to 'int' [-Wimplicit-int]
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      | ^~~~
main.c: In function 'main':
main.c:2:1: error: type of 'a' defaults to 'int' [-Wimplicit-int]
main.c:2:1: error: type of 'b' defaults to 'int' [-Wimplicit-int]
main.c:2:1: error: type of 'i' defaults to 'int' [-Wimplicit-int]
main.c:2:18: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                  ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | #define p printf("
main.c:2:18: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                  ^~~~~
main.c:2:18: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:2:44: error: stray '\' in program
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                            ^
main.c:2:42: error: 's' undeclared (first use in this function)
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                          ^
main.c:2:42: note: each undeclared identifier is reported only once for each function it appears in
main.c:2:43: error: expected ')' before 'n'
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                ~                          ^ ~
      |                                           )
main.c:2:64: error: expected statement before ')' token
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                ^
main.c:1:11: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | #define p printf("
      |           ^~~~~~
main.c:2:78: note: in expansion of macro 'p'
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                              ^
main.c:1:11: note: include '<stdio.h>' or provide a declaration of 'printf'
    1 | #define p printf("
      |           ^~~~~~
main.c:2:78: note: in expansion of macro 'p'
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                              ^
main.c:1:11: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
    1 | #define p printf("
      |           ^~~~~~
main.c:2:78: note: in expansion of macro 'p'
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                              ^
main.c:1:11: note: include '<stdio.h>' or provide a declaration of 'printf'
    1 | #define p printf("
      |           ^~~~~~
main.c:2:78: note: in expansion of macro 'p'
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                              ^
main.c:1:18: error: missing terminating " character
    1 | #define p printf("
      |                  ^
main.c:2:78: note: in expansion of macro 'p'
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                              ^
main.c:2:80: error: expected expression before '%' token
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                                ^
main.c:2:93: error: stray '#' in program
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                                             ^
main.c:2:98: warning: missing terminating " character
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                                                  ^
main.c:2:98: error: missing terminating " character
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                                                  ^~~~~~~
main.c:2:80: error: expected declaration or statement at end of input
    2 | main(a,b,i){for(;scanf("%d%d",&a,&b),a+b;s \n")){for(;a--; \n")){for(i=b;i--;p %s",(a+i)%2?"#":"."));}}}
      |                                                                                ^
main.c:2:80: error: expected declaration or statement at end of input