CC++ 133 bytes
#include <iostream> #include <cstdlib> using namespace std; int main(int argc, char *argv[]){ printf("%s", variable); return 0; } Displays the error (132 bytes):
.code.tio.c: In function ‘main’: .code.tio.c:5:14: error: ‘variable’ undeclared (first use in this function) printf("%s", variable);