小编use*_*931的帖子

为了做出以下类型的断言

create assertion assert  
check "EMPTY SET" = (select User         
     from Video  
     where date=current_date()  
     group by user  
having count(*) >= 10

这个说法是对的吗？

create assertion assert  
check  0 = (select count(*)  
     from Video  
     where date=current_date()  
     group by user  
having count(*) >= 10

请看一下这两段伪汇编代码：

1)

li $t0,53

sll $t1,$t0,2
srl $t2,$t0,2
sra $t3,$t0,2

print $t1  
print $t2  
print $t3  

2)

li $t0,-53


sll $t1,$t0,2
srl $t2,$t0,2
sra $t3,$t0,2

print $t1
print $t2
print $t3

在第一种情况下，输出为：
212
13
13

后者是：
-212
107374...
-14
但不应该：sra (-53) = - (srl 53) ？

Wikipidea说,Perl有一个显性实现,可用作其规范的参考,而C语言则由标准ANSI ISO指定.

我学会了C语言而没有阅读单行标准,这是正常的吗？

我想知道标准(即自然语言文档)如何能够描述编程语言而不涉及任何主导实现.

以下函数必须将一条线分成2行或更多行,每行比s短.

char **splitline(FILE *fp, int s)
{
    char **l;
    char c;
    int ccounter;
    int lcounter;

    c = fgetc(fp);
    if (c == EOF)
    {
        return NULL;
    }

    lcounter=0;
    l = malloc(sizeof(char **));
    l[lcounter] = malloc((SIZE+2)*sizeof(char));

    ccounter = 0;
    while (c != EOF && c != '\n')
    {
        l[lcounter][ccounter] = c;
        ccounter++;
        c = fgetc(fp);

        if (ccounter == SIZE)
        {
            l[lcounter][ccounter] = '\n';
            ccounter++;
            l[lcounter][ccounter] = '\0';

            realloc(l, (lcounter+2) * sizeof(char **));

            lcounter++;

            l[lcounter] = malloc((SIZE+2) * sizeof(char));
            ccounter = 0;
        } …