Question

72) Given a character pointer p_ch, and integer pointer p_int, and a float pointer, p_f, how many bytes will be added/subtracted, respectively, in the following expressions: (assume that char is 1 byte, int 4 bytes, and float 4 bytes, respectively)   

            a)         p_ch - 4

            b)         p_int + 20

            c)        p_f + 13

            d)         p_int - 1

            e)         p_f – 1

Answer 1

First of all let me tell you, a pointer is always of 4 byte long whatever data type it is pointing. It take always 4 byte memory in 32/64bit compiler.

Now come to question. as you mentioned in question, for part a 4 should be character data type so it is of 1 byte size.

(a) pointer size = 4
and a character is being subtracted that is of 1 byte so here 1 byte will be subtracted. ( 4(pointer size) -1(4, that is another character to be subtracted size of 1 byte))

(b) in b part, operation are being performed on int data type, 20 is int so its size is 4 byte as mentioned in question

so 4 byte will be added,

4 byte of p_int pointer size and 4 byte of integer(20)


(c)  in c part, operation are being performed on float data type, 13 is float so its size is 4 byte as mentioned in question

so 4 byte will be added,

4 byte of p_int pointer size and 4 byte of float(13)

(d)  in d part, operation are being performed on int data type, 1 is int so its size is 4 byte as mentioned in question

so 4 byte will be subtracted,

4 byte of p_int pointer and 4 byte of integer(1)

(e) in e part, operation are being performed on float data type, 1 is float so its size is 4 byte as mentioned in question

so 4 byte will be subtracted,

4 byte of p_f pointer and 4 byte of float(13)




Hope this helps!

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