prog.c: In function ‘main’:
prog.c:6:2: warning: implicit declaration of function ‘Scanf’ [-Wimplicit-function-declaration]
Scanf("%d",&a);
^~~~~
/home/NRLU0m/cc0tZ7kY.o: In function `main':
prog.c:(.text.startup+0x26): undefined reference to `Scanf'
collect2: error: ld returned 1 exit status