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Psql list all tables
...This is where the INFORMATION_SCHEMA comes to the rescue. To list tables:
SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';
BTW, if you ever want to see what psql is doing in response to a backslash command, run psql with the -E flag. eg:
$ psql -E regress
regre...
How do function pointers in C work?
... class:
typedef struct String_Struct* String;
struct String_Struct
{
char* (*get)(const void* self);
void (*set)(const void* self, char* value);
int (*length)(const void* self);
};
char* getString(const void* self);
void setString(const void* self, char* value);
int lengthString(const...
How to get the separate digits of an int number?
...
Convert it to String and use String#toCharArray() or String#split().
String number = String.valueOf(someInt);
char[] digits1 = number.toCharArray();
// or:
String[] digits2 = number.split("(?<=.)");
In case you're already on Java 8 and you happen to want t...
What should main() return in C and C++?
.... The valid C++ main signatures are:
int main()
and
int main(int argc, char* argv[])
which is equivalent to
int main(int argc, char** argv)
It is also worth noting that in C++, int main() can be left without a return-statement, at which point it defaults to returning 0. This is also true wi...
Difference between fprintf, printf and sprintf?
...tream is currently pointing.
sprintf writes formatted text to an array of char, as opposed to a stream.
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How come an array's address is equal to its value in C?
...rray, not the size of a single element. For example, with code like this:
char array[16];
printf("%p\t%p", (void*)&array, (void*)(&array+1));
We can expect the second pointer to be 16 greater than the first (because it's an array of 16 char's). Since %p typically converts pointers in hexa...
Best way to replace multiple characters in a string?
I need to replace some characters as follows: & ➔ \& , # ➔ \# , ...
13 Answers
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How to convert integer to string in C? [duplicate]
...
Use sprintf():
int someInt = 368;
char str[12];
sprintf(str, "%d", someInt);
All numbers that are representable by int will fit in a 12-char-array without overflow, unless your compiler is somehow using more than 32-bits for int. When using numbers with gre...
Parsing command-line arguments in C?
... write a program that can compare two files line by line, word by word, or character by character in C. It has to be able to read in command line options -l -w -i or -- ...
...
Templated check for the existence of a class member function?
...SFINAE test
template <typename T>
class has_helloworld
{
typedef char one;
struct two { char x[2]; };
template <typename C> static one test( decltype(&C::helloworld) ) ;
template <typename C> static two test(...);
public:
enum { value = sizeof(test<...
