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How do I concatenate two strings in C?
... some other languages have. A string in C is just a pointer to an array of char that is terminated by the first null character. There is no string concatenation operator in C.
Use strcat to concatenate two strings. You could use the following function to do it:
#include <stdlib.h>
#include &...
How to append a char to a std::string?
...ing fails with the error prog.cpp:5:13: error: invalid conversion from ‘char’ to ‘const char*’
13 Answers
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How do I remove all non alphanumeric characters from a string except dash?
How do I remove all non alphanumeric characters from a string except dash and space characters?
13 Answers
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Get difference between two lists
...the following simple function.
def diff(list1, list2):
c = set(list1).union(set(list2)) # or c = set(list1) | set(list2)
d = set(list1).intersection(set(list2)) # or d = set(list1) & set(list2)
return list(c - d)
or
def diff(list1, list2):
return list(set(list1).symmetric_d...
How to concatenate twice with the C preprocessor and expand a macro as in “arg ## _ ## MACRO”?
...ER(x,y)
#define NAME(fun) EVALUATOR(fun, VARIABLE)
extern void NAME(mine)(char *x);
$ gcc -E xx.c
# 1 "xx.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "xx.c"
extern void mine_3(char *x);
$
Two levels of indirection
In a comment to another answer, Cade Roux asked why this needs t...
How to printf uint64_t? Fails with: “spurious trailing ‘%’ in format”
... I wonder if there are progress towards a locale independent and/or locale selectable version of std::to_string(). The cppreference page still link only to std::to_chars(), which is not really what people need. I wonder if fmt and/or c++20 deal with it or not yet.
– ceztko
...
What's a quick way to comment/uncomment lines in Vim?
...
For those tasks I use most of the time block selection.
Put your cursor on the first # character, press CtrlV (or CtrlQ for gVim), and go down until the last commented line and press x, that will delete all the # characters vertically.
For commenting a block of text i...
Why declare a struct that only contains an array in C?
...ever you declare such an object. This could also be achieved with
typedef char ABC[MAX];
but then you have a much bigger problem: you have to be aware that ABC is an array type (even though you can't see this when you declare variables of type ABC) or else you'll get stung by the fact that ABC wi...
How to send a simple string between two programs using pipes?
...lt;sys/types.h>
#include <unistd.h>
int main()
{
int fd;
char * myfifo = "/tmp/myfifo";
/* create the FIFO (named pipe) */
mkfifo(myfifo, 0666);
/* write "Hi" to the FIFO */
fd = open(myfifo, O_WRONLY);
write(fd, "Hi", sizeof("Hi"));
close(fd);
/* rem...
Getting the first character of a string with $str[0]
...
Yes. Strings can be seen as character arrays, and the way to access a position of an array is to use the [] operator. Usually there's no problem at all in using $str[0] (and I'm pretty sure is much faster than the substr() method).
There is only one ca...