c++ - c语言指针运算问题

Question

c 指针运算问题？修改
一、代码：

int a[]={1,2,3,4,5};
int *p;
p=a;
*(p++)=10;
int i;
for (i=0; i<sizeof(a)/sizeof(int); i++) {
printf("a[%d]=%d\n",i,a[i]);
}

输出：
a[0]=10
a[1]=2
a[2]=3
a[3]=4
a[4]=5
二、问题
明明指针往下移了，为什么a[0]=10,而不是a[1]=10?

Answer 1

p++
++ followed by
is equivalent to

*(p)=10;
p++

is different from ++p

Answer 2

(p++)=10 (p++) returns the subscript of 0, so the result is like this. In fact, your sentence is equivalent to p++, and the result is the same

Answer 3

p++ will return the value before it is incremented, and p will not be incremented until the end of the expression evaluation phase. Here *p++ can be regarded as a subexpression.

Answer 4

P++ If you are not familiar with it, use it sparingly. It won’t save much cost. It’s a simple matter of calculating first and then assigning a value, and first assigning a value and then calculating.

Answer 5

#include <stdio.h>
int main()
{

    int a[]={1,2,3,4,5};
    int *p;
    p=a;
    *(p+1)=10;
    p++;
    int i;
    for (i=0; i<sizeof(a)/sizeof(int); i++) {
        printf("a[%d]=%d\n",i,a[i]);
    }
}

Answer 6

p++ and p are exactly the same, ++p is equal to (p+1), but no matter what, these two things exist in the subsequent code p=p+1. (If you still don’t understand, read the book yourself)

Answer 7

There is a simple method for you to understand: you can print p, p++ in sequence ((p++) still takes the scalar value p++, or here you can output &((p++)) ) and p. After looking at the results, you will understand that the memory address of *(p++) is still p, and then it becomes p+1

Answer 8

The difference between "prefix++" and "suffix++", classic test questions in c/c++