What will this C code do?

void main(){
int x=1;
printf("%d\n",x=2);
}

>>73
In some cases, what will happen, is that the variable will no longer be a tentative definition once the translation unit is completed. In other words, the uninitialized variable will in fact, become initialized. And depending on what you're trying to achieve, initializing the varible in such a case may in fact hinder the performance of the program.