C语言问题求教

[goooooooooooogle]

void str_cat()
{
    char string[48];
    memset(string,0,sizeof(string));
    char string1[12] = "Hi!";
    char string2[12] = "Xiaoming,";
    char string3[12] = "Good morning!";

    strcat(string, string1);
    strcat(string, string2);
    strcat(string, string3);

    printf("%s \n", string);  
}

打印结果为啥是：Hi!Xiaoming,Good morningXiaoming,
而不是：Hi!Xiaoming,Good morning!

[Jim_King_2000]

char string3[12] = "Good morning!";
貌似12个字符不够啊。让编译器自动决定有多少个字符比较好。
char string3[] = "Good morning!";

[程序员小迷]

char string3[12] = "Good morning!";
越界

[程序员小迷]

string2在string3地址的高处，正好会接着string2打印

[justkk]

嗯，string3的空间不足
编译器没有告警？

[程序员小迷]

gcc4.2直接报错

[Isnis-fallen]

除了string3溢出, 不会出现显示错误Hi!Xiaoming,Good morningXiaoming,

[hanyunqi]

char string2[12] = "Xiaoming,";
char string3[12] = "Good morning!";
这两个数组长度不够,改为:
char string2[18] = "Xiaoming,";
char string3[18] = "Good morning!";
测试通过,输出结果为:
Hi!Xiaoming,Good morning!