Language: C

#define A atoi(c+4)
char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}

Compiler output:
main.c:2:10: warning: data definition has no type or storage class
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |          ^
main.c:2:10: error: type defaults to 'int' in declaration of 's' [-Wimplicit-int]
main.c:2:22: error: type defaults to 'int' in declaration of 'p' [-Wimplicit-int]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                      ^
main.c:2:28: error: return type defaults to 'int' [-Wimplicit-int]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                            ^~~~
main.c: In function 'main':
main.c:2:28: error: type of 'i' defaults to 'int' [-Wimplicit-int]
main.c:2:40: error: implicit declaration of function 'gets' [-Wimplicit-function-declaration]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                        ^~~~
main.c:2:65: error: implicit declaration of function 'atoi' [-Wimplicit-function-declaration]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                 ^~~~
main.c:2:76: error: implicit declaration of function 'log10' [-Wimplicit-function-declaration]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                            ^~~~~
main.c:1:1: note: include '<math.h>' or provide a declaration of 'log10'
  +++ |+#include <math.h>
    1 | #define A atoi(c+4)
main.c:2:76: warning: incompatible implicit declaration of built-in function 'log10' [-Wbuiltin-declaration-mismatch]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                            ^~~~~
main.c:2:76: note: include '<math.h>' or provide a declaration of 'log10'
main.c:2:75: error: invalid operands to binary + (have 'char *' and 'double')
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                        ~~~^~~~~~~~~
      |                                                                         |  |
      |                                                                         |  double
      |                                                                         char *
main.c:2:130: error: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                                                                                  ^~~~~~
main.c:1:1: note: include '<string.h>' or provide a declaration of 'strlen'
  +++ |+#include <string.h>
    1 | #define A atoi(c+4)
main.c:2:130: warning: incompatible implicit declaration of built-in function 'strlen' [-Wbuiltin-declaration-mismatch]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                                                                                  ^~~~~~
main.c:2:130: note: include '<string.h>' or provide a declaration of 'strlen'
main.c:2:143: error: implicit declaration of function 'puts' [-Wimplicit-function-declaration]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                                                                                               ^~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'puts'
  +++ |+#include <stdio.h>
    1 | #define A atoi(c+4)
main.c:2:152: error: passing argument 1 of 'puts' from incompatible pointer type [-Wincompatible-pointer-types]
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |                                                                                                                                                    ~~~~^~~~~~~
      |                                                                                                                                                        |
      |                                                                                                                                                        int *
main.c:2:152: note: expected 'const char *' but argument is of type 'int *'
main.c: At top level:
main.c:2:6: warning: array 'c' assumed to have one element
    2 | char c[];s[99][1000],p[99];main(i){for(gets(c);gets(c);*c&4?s[i=atoi(i=c+7+log10(A))][p[i]++]=s[A][--p[A]]:c[2]&1?s[A][p[A]++]=c[strlen(c)-1]:puts(s[A]+--p[A]));}
      |      ^