Why answer is 64 , can anyone help me

Question

int main() {
int a=320;
char *ptr;
ptr=(char*)&a;
printf ("%d",*ptr);
}

Answer 1

320 in decimal equals to 101000000 in binary (it needs 9 bits to fit in) however a char is 8 bits.
casting a char from an int gives the lowest byte (least significant 8 bits) which in this case is 01000000 and that's 64 in decimal.
the code without using pointers can be written as:
printf("%d", (char)320);
or
int a = 320;
printf("%d", (char)a);