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print call stack in C or C++
...oid my_func_1(int i) {
(void)i;
my_func_2();
}
int main(int argc, char **argv) {
long long unsigned int n;
if (argc > 1) {
n = strtoul(argv[1], NULL, 0);
} else {
n = 1;
}
for (long long unsigned int i = 0; i < n; ++i) {
my_func_1(1); // l...
C++ Convert string (or char*) to wstring (or wchar_t*)
...nclude <string>
std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
std::string narrow = converter.to_bytes(wide_utf16_source_string);
std::wstring wide = converter.from_bytes(narrow_utf8_source_string);
Longer online compilable and runnable example:
(They all sho...
How do I URL encode a string
I have a URL string ( NSString ) with spaces and & characters. How do I url encode the entire string (including the & ampersand character and spaces)?
...
Simple C example of doing an HTTP POST and consuming the response
...lude <netdb.h> /* struct hostent, gethostbyname */
void error(const char *msg) { perror(msg); exit(0); }
int main(int argc,char *argv[])
{
/* first what are we going to send and where are we going to send it? */
int portno = 80;
char *host = "api.somesite.com";
...
Reading a string with scanf
...tring[0]). On the other hand, scanf("%s", &string) passes a pointer-to-char[256], but it points to the same place.
Then scanf, when processing the tail of its argument list, will try to pull out a char *. That's the Right Thing when you've passed in string or &string[0], but when you've pas...
How do I put a variable inside a string?
...
Oh, the many, many ways...
String concatenation:
plot.savefig('hanning' + str(num) + '.pdf')
Conversion Specifier:
plot.savefig('hanning%s.pdf' % num)
Using local variable names:
plot.savefig('hanning%(num)s.pdf' % locals()) # Neat trick
Using str.fo...
Is there a REAL performance difference between INT and VARCHAR primary keys?
Is there a measurable performance difference between using INT vs. VARCHAR as a primary key in MySQL? I'd like to use VARCHAR as the primary key for reference lists (think US States, Country Codes) and a coworker won't budge on the INT AUTO_INCREMENT as a primary key for all tables.
...
How to convert a number to string and vice versa in C++
...ersion succeeded and idx is not 0, idx will contain the index of the first character that was not used for decoding. This could be an index behind the last character.
Finally, the integral types allow to specify a base, for digits larger than 9, the alphabet is assumed (a=10 until z=35). You can fi...
How to open, read, and write from serial port in C?
...ed);
tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8; // 8-bit chars
// disable IGNBRK for mismatched speed tests; otherwise receive break
// as \000 chars
tty.c_iflag &= ~IGNBRK; // disable break processing
tty.c_lflag = 0; // n...
The tilde operator in C
... operator. It inverts the bits of the operand.
For example, if you have:
char b = 0xF0; /* Bits are 11110000 */
char c = ~b; /* Bits are 00001111 */
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