C中調(diào)用函數(shù)之前的參數(shù)求值順序在C中調(diào)用函數(shù)參數(shù)時(shí)，可以假定函數(shù)參數(shù)的賦值順序嗎？根據(jù)下面的程序，當(dāng)我執(zhí)行它時(shí)，似乎沒有一個(gè)特定的命令。#include <stdio.h>int main(){
int a[] = {1, 2, 3};
int * pa;
pa = &a[0];
printf("a[0] = %d\ta[1] = %d\ta[2] = %d\n",*(pa), *(pa++),*(++pa));
/* Result: a[0] = 3 a[1] = 2 a[2] = 2 */
pa = &a[0];
printf("a[0] = %d\ta[1] = %d\ta[2] = %d\n",*(pa++),*(pa),*(++pa));
/* Result: a[0] = 2 a[1] = 2 a[2] = 2 */
pa = &a[0];
printf("a[0] = %d\ta[1] = %d\ta[2] = %d\n",*(pa++),*(++pa), *(pa));
/* a[0] = 2 a[1] = 2 a[2] = 1 */}
3 回答
www說
TA貢獻(xiàn)1775條經(jīng)驗(yàn) 獲得超8個(gè)贊
慕虎7371278
TA貢獻(xiàn)1802條經(jīng)驗(yàn) 獲得超4個(gè)贊
函數(shù)指示符、實(shí)際參數(shù)中的實(shí)際參數(shù)和子表達(dá)式的計(jì)算順序未指定，但在實(shí)際調(diào)用之前有一個(gè)序列點(diǎn)。
pa
$ gcc -Wall -W -ansi -pedantic test.c -o test test.c: In function ‘main’:test.c:9: warning: operation on ‘pa’ may be undefined test.c:9: warning: operation on ‘pa’ may be undefined test.c:13: warning: operation on ‘pa’ may be undefined test.c:13: warning: operation on ‘pa’ may be undefined test.c:17: warning: operation on ‘pa’ may be undefined test.c:17: warning: operation on ‘pa’ may be undefined test.c:20: warning: control reaches end of non-void function
斯蒂芬大帝
TA貢獻(xiàn)1827條經(jīng)驗(yàn) 獲得超8個(gè)贊
int i=1;printf("%d %d %d\n", i++, i++, i);2 1 31 2 32 1 31 2 31 2 31 2 3
- 3 回答
- 0 關(guān)注
- 608 瀏覽
添加回答
舉報(bào)
0/150
提交
取消