为什么后缀的优先级高于前缀？

Question

案例 1：

int i = 10;
int j = i++;

这里先把i的值赋给j，然后i加1。

案例二：

int i = 10;
int j = ++i;

这里先把i加1赋值给j

那么，如果前缀形式先进行自增操作，那为什么后缀比前缀高呢？

Answer 1

这与优先级无关。（此处）在预增量中，分配的值是副作用发生之前的值。对于预增量，它将是副作用后的值。

int i = 10;
int j = i++;

在 i 的递增值之前是 10。因此 j=10 在执行这 2 个语句之后。

int i = 10;
int j = ++i;

这里的值会是11。因为incremenet是先完成后赋值的。

Answer 2

Linux manual operator 页定义为 same priority pre/post increment.

! ~ ++ -- + - (type) * & sizeof      right to left

post增量规则先赋值再增量

int j = i++;// here first whatever i value is there that will be assigned to j

预自增规则是先自增再赋值

int j = ++i;//++i itself will change i value & then modfied value will assign to j.

例如考虑下面的例子

#include<stdio.h>
int main()
{
        int x = 10;
        int *p = &x;// assume p holds 0x100
        printf("x = %d *p = %d p = %p\n",x,*p,p);
        ++*p++;
        /** in above statement ++ and * having same precedence,then you should check assocaitivity which is R to L
          So start solving from Right to Left, whichever operator came first , solve that one first 
          first *p++ came , again solve p++ first, which is post increment,so address will be same 
         *0x100  means = 10
         now ++10 means = 11
         **/
        printf("x = %d *p = %d p = %p\n",x,*p,p);
}

为什么后缀的优先级高于前缀？

Why postfixed has higher precedence than prefixed?

c

operator-precedence