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Undefined reference to static constexpr char[]
I want to have a static const char array in my class. GCC complained and told me I should use constexpr , although now it's telling me it's an undefined reference. If I make the array a non-member then it compiles. What is going on?
...
Avoid trailing zeroes in printf()
...") the number to a string buffer then manipulate the string to only have N characters past the decimal point.
Assuming your number is in the variable num, the following function will remove all but the first N decimals, then strip off the trailing zeros (and decimal point if they were all zeros).
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Java String - See if a string contains only numbers and not letters
...> 2) {
Instead of checking that the string doesn't contain alphabetic characters, check to be sure it contains only numerics.
If you actually want to use the numeric value, use Integer.parseInt() or Double.parseDouble() as others have explained below.
As a side note, it's generally consider...
C语言结构体里的成员数组和指针 - c++1y / stl - 清泛IT社区，为创新赋能！
...#include <stdio.h>
struct str{
int len;
char s[0];
};
struct foo {
struct str *a;
};
int main(int argc, char** argv) {
struct foo f={0};
if (f.a->s) {
printf( f.a->s);
&...
“sending 'const NSString *' to parameter of type 'NSString *' discards qualifiers” warning
...he term on its right only if there's nothing on its left side (e. g. const char * and a char const * are non-const pointers to const char, but char *const is a const pointer to non-const char).
– user529758
Oct 11 '12 at 4:29
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Callback functions in C++
... for jumping, the engine can call
game_core_instance.update_keybind(newly_selected_key, &player_jump);
and thus change the behaviour of a call to key_pressed (which the calls player_jump) once this button is pressed the next time ingame.
What are callables in C++(11)?
See C++ concepts: Call...
How to define an enum with string value?
...value with each enum value, or in this case if every separator is a single character you could just use the char value:
enum Separator
{
Comma = ',',
Tab = '\t',
Space = ' '
}
(EDIT: Just to clarify, you can't make char the underlying type of the enum, but you can use char constants t...
Regarding 'main(int argc, char *argv[])' [duplicate]
Every program is starting with the main(int argc, char *argv[]) definition.
8 Answers
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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...
error C2664: “find_char”: 不能将参数 1 从“const char [14]”转换为“...
error C2664: “find_char”: 不能将参数 1 从“const char [14]”转换为“std::string &出错代码：#include <iostream>#include <string>using std::cout;using std::endl;using std::string; const引用形参举例 非const...出错代码：
#include <iostream>
#include <string>
using...