#include <stdio.h> /* only one # */
/* Don't declare your variables here unless you have a reason to do so.
That would make them global variables.
Instead, make them local variables by declaring them inside the main function. */
int C, F; /*note: no quotes, and there must be a semicolon at end of each line
(EXCEPT preprocessor directives */
printf("Enter today's temp in Celsius > ");
scanf("%d",&C); /* What's Feh? You want to input a value for C.
And note, it's &C, not %C */
printf("F is ");
printf("%d", F); /* Note, in printf, no & before the variable name*/