var_stack_array.c

#ifdef SHELL
gcc -Wall -Werror $0 && ./a.out 10
exit 0
#endif

#include <stdio.h>
#include <stdlib.h>
 
int main( int argc, char * argv [] ) {
  int size = atoi(argv[1]);
  char data[size+1];
  data[size] = '\0';
  int i;
  for( i = 0; i < size; i++ ) {
     if ( i%2 == 0 )
       data[i] = 'A' + (i/2)%('9'-'0');
     else
       data[i] = 'T';
  }
  printf("Result = %s\n", data);
  return 0;
}