Subtracting two pointers giving unexpected result

Question

#include 

int main() {
    int *p = 100;
    int *q = 92;
    printf(\"%d\\n\", p - q);  //prints 2
}

Shouldn\'t the output of above pr

Answer 1

int main() {
    int *p = 100;
    int *q = 92;
    printf("%d\n", p - q);  //prints 2
}

It is called pointer arthmetic what happens there.

The value will be (100-92)/sizeof(int). In your case sizeof(int)=4.

In ISO9899 pointer arithmetic is defined so for subtraction ptr-ptr. Chapter 6.5.6p9

When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object; the result is the difference of the subscripts of the two array elements.