大约有 41,000 项符合查询结果（耗时：0.0209秒） [XML]
NULL values inside NOT IN clause
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Query A is the same as:
select 'true' where 3 = 1 or 3 = 2 or 3 = 3 or 3 = null
Since 3 = 3 is true, you get a result.
Query B is the same as:
select 'true' where 3 <> 1 and 3 <> 2 and 3 <> null
When ansi_nulls is on, 3 <&...
Objective-C : BOOL vs bool
...mp; __LP64__) || TARGET_OS_WATCH
typedef bool BOOL;
#else
typedef signed char BOOL;
// BOOL is explicitly signed so @encode(BOOL) == "c" rather than "C"
// even if -funsigned-char is used.
#endif
#define YES ((BOOL)1)
#define NO ((BOOL)0)
So, yes, you can assume that BOOL is a char. You can ...
How can I increment a char?
I'm new to Python, coming from Java and C. How can I increment a char? In Java or C, chars and ints are practically interchangeable, and in certain loops, it's very useful to me to be able to do increment chars, and index arrays by chars.
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Count occurrences of a char in a string using Bash
I need to count the number of occurrences of a char in a string using Bash.
7 Answers
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String literals: Where do they go?
... dependent on your platform and could change over time), just use arrays:
char foo[] = "...";
The compiler will arrange for the array to get initialized from the literal and you can modify the array.
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Is there an auto increment in sqlite?
... In case it is not obvious from answer, you can use ROWID in your select statement e.g. select rowid from people;
– Colin D
Mar 20 '17 at 15:37
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Types in Objective-C on iOS
...e:
32 bit process:
NSLog(@"Primitive sizes:");
NSLog(@"The size of a char is: %d.", sizeof(char));
NSLog(@"The size of short is: %d.", sizeof(short));
NSLog(@"The size of int is: %d.", sizeof(int));
NSLog(@"The size of long is: %d.", sizeof(long));
NSLog(@"The size of long long is: %d....
C++ performance challenge: integer to std::string conversion
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#include <string>
const char digit_pairs[201] = {
"00010203040506070809"
"10111213141516171819"
"20212223242526272829"
"30313233343536373839"
"40414243444546474849"
"50515253545556575859"
"60616263646566676869"
"70717273747576777879"...
Difference between Char.IsDigit() and Char.IsNumber() in C#
What's the difference between Char.IsDigit() and Char.IsNumber() in C#?
3 Answers
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Implicit type conversion rules in C++ operators
...re promoted to int
Note. The minimum size of operations is int. So short/char are promoted to int before the operation is done.
In all your expressions the int is promoted to a float before the operation is performed. The result of the operation is a float.
int + float => float + float = flo...