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How to determine if a string is a number with C++?
...nt way would be just to iterate over the string until you find a non-digit character. If there are any non-digit characters, you can consider the string not a number.
bool is_number(const std::string& s)
{
std::string::const_iterator it = s.begin();
while (it != s.end() && std:...
Is an array name a pointer?
...no storage is materialized for a separate pointer or any metadata. Given
char a[10];
what you get in memory is
+---+
a: | | a[0]
+---+
| | a[1]
+---+
| | a[2]
+---+
...
+---+
| | a[9]
+---+
The expression a refers to the entire array, but there's no obj...
Objective-C formatting string for boolean?
...
In Objective-C, the BOOL type is just a signed char. From <objc/objc.h>:
typedef signed char BOOL;
#define YES (BOOL)1
#define NO (BOOL)0
So you can print them using the %d formatter But that will only print a 1 or a 0, not YES or NO.
Or you can...
Android Reading from an Input stream efficiently
... avoid creating new String objects on each append and to avoid copying the char arrays. The implementation for your case would be something like this:
BufferedReader r = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder total = new StringBuilder();
for (String line; (line = r.re...
What do single quotes do in C++ when used on multiple characters?
...
It's a multi-character literal. 1952805748 is 0x74657374, which decomposes as
0x74 -> 't'
0x65 -> 'e'
0x73 -> 's'
0x74 -> 't'
Edit:
C++ standard, §2.14.3/1 - Character literals
(...) An ordinary character literal that conta...
Write to .txt file?
...intf("Error opening file!\n");
exit(1);
}
/* print some text */
const char *text = "Write this to the file";
fprintf(f, "Some text: %s\n", text);
/* print integers and floats */
int i = 1;
float py = 3.1415927;
fprintf(f, "Integer: %d, float: %f\n", i, py);
/* printing single chatacters */
ch...
string c_str() vs. data()
...orm better than c_str().
strings don't necessarily have to be composed of character data, they could be composed with elements of any type. In those cases data() is more meaningful. c_str() in my opinion is only really useful when the elements of your string are character based.
Extra: In C++11 on...
What is the point of function pointers?
...at, float) -> float function
typedef int (TMyClass::*pt2Member)(float, char, char);
// defines a symbol pt2Member, pointer to a (float, char, char) -> int function
// belonging to the class TMyClass
The only time I have ever seen function pointers used where functors could not was in Bo...
OceanBase使用libeasy原理源码分析：服务器端 - 数据库(内核) - 清泛网 - ...
...EASY_OK,则signal信号量，从而工作线程被唤醒。
典型的，select请求这种需要回复多个包给MySQL客户端的场景使用的都是这种模式
其它诸如只需要回复一个包给MySQL客户端的DML操作，例如INSERT,UPDATE等也使用这种模式，只是工作线程...
Difference between angle bracket < > and double quotes “ ” while including header files in C++? [dup
...tion 6.10.2):
A preprocessing directive of the form
# include <h-char-sequence> new-line
searches a sequence of implementation-defined places for a header identified uniquely by the specified sequence between the < and > delimiters, and causes the replacement of that directi...