大约有 22,000 项符合查询结果（耗时：0.0267秒） [XML]
What is the optimal length for an email address in a database?
...s though.
Again, since a varchar only uses the space actually used by the string you store, there is no reason to have a small limit for email address length. Just go with 512 and stop worrying. Everything else is premature optimization
...
Why do we need argc while there is always a null at the end of argv?
...arynkevitch Time of merely stepping through an array of pointer values one extra time until NULL, to get the count, is miniscule compared to time already spent generating the pointer array, and even more irrelevant compared to actually using each argument value in the program. And if just checking i...
Is there a splice method for strings?
...he Javascript splice only works with arrays. Is there similar method for strings? Or should I create my own custom function?
...
How do I read an entire file into a std::string in C++?
How do I read a file into a std::string , i.e., read the whole file at once?
15 Answers
...
How to use GROUP BY to concatenate strings in SQL Server?
...
A slightly cleaner way of doing the string manipulation: STUFF((SELECT ', ' + [Name] + ':' + CAST([Value] AS VARCHAR(MAX)) FROM #YourTable WHERE (ID = Results.ID) FOR XML PATH ('')),1,2,'') AS NameValues
– Jonathan Sayce
...
Capitalize first letter. MySQL
...= CONCAT(UCASE(LEFT(CompanyIndustry, 1)),
SUBSTRING(CompanyIndustry, 2));
This would turn hello to Hello, wOrLd to WOrLd, BLABLA to BLABLA, etc. If you want to upper-case the first letter and lower-case the other, you just have to use LCASE function :
UPDATE tb_Compa...
Write to .txt file?
...
FILE *fp;
char* str = "string";
int x = 10;
fp=fopen("test.txt", "w");
if(fp == NULL)
exit(-1);
fprintf(fp, "This is a string which is written to a file\n");
fprintf(fp, "The string has %d words and keyword %s\n", x, str);
fclose(fp);
...
Test whether string is a valid integer
...aining it so I can learn a little? I gather it reads, "At the start of the string (^), a minus sign (-) is optional (?), followed by any number of characters between zero and 9, inclusive" ... and what then might the +$ mean? Thanks.
– Richard T
Feb 5 '10 at 21...
C++11 tuple 这一篇就够了 - C/C++ - 清泛网 - 专注C/C++及内核技术
...的多个tuple）。
#include <iostream>
#include <utility>
#include <string>
#include <tuple>
int main ()
{
std::tuple<float,std::string> mytuple (3.14,"pi");
std::pair<int,char> mypair (10,'a');
auto myauto = std::tuple_cat ( mytuple, mypair );
std::cout << "myauto contai...
std::stringstream ss; 直接使用ss.str().c_str() 字符串指针可能导致崩溃 ...
std::stringstream ss; 直接使用ss.str().c_str() 字符串指针可能导致崩溃std::stringstream ss;const char* ch = ss str() c_str();call_func(ch);这种写法在系统内存不足时，ss会立马释放内存，字符串指针ch可能会非法访问导致崩溃。代码最好的是
std::s...