int a [] = {1,2，};允许使用怪异的逗号。有什么特殊原因吗？

#1 楼

int a[] = {
   1,
   2,
   3
};

#2 楼

int a[] = {
  1,
  2,
  3, //You can delete this line and it's still valid
};

#3 楼

int a[] = {
            1,
            2,
            2,
            2,
            2,
            2, /*line I could comment out easily without having to remove the previous comma*/
          }

#4 楼

int a[] = {
            5,
            6,
          };

#5 楼

int ints[] = {
    3,
    9
};

int ints[] = {
    3,
    9,
    12
};

int ints[] = {
    1,
    3,
    9
};

#6 楼

for_each(my_inits.begin(), my_inits.end(),
[](const std::string& value) { std::cout << value << ",\n"; });

#7 楼

#8 楼

std::cout << "enum Items {\n";
for(Items::iterator i(items.begin()), j(items.end); i != j; ++i)
    std::cout << *i << ",\n";
std::cout << "};\n";

#9 楼

#10 楼

#11 楼

int a[] = {
   1,
   2,
   //3, // - not needed any more
};

#12 楼

#13 楼

#14 楼

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    puts("Line 1");
    puts("Line 2");
    puts("Line 3");

    return EXIT_SUCCESS
}

#15 楼

#include <iostream>
#include <string>
#include <cstddef>
#define ARRAY_SIZE(array) (sizeof(array) / sizeof *(array))
int main() {
    std::string messages[] = {
        "Stack Overflow",
        "Super User",
        "Server Fault"
    };
    size_t i;
    for (i = 0; i < ARRAY_SIZE(messages); i++) {
        std::cout << messages[i] << std::endl;
    }
}

Stack Overflow
Super User
Server Fault

#16 楼

char *available_resources[] = {
"color monitor"           ,
"big disk"                ,
"Cray"                      /* whoa! no comma! */
"on-line drawing routines",
"mouse"                   ,
"keyboard"                ,
"power cables"            , /* and what's this extra comma? */
};

#17 楼

#18 楼

#define LIST_BEGIN int a[] = {
#define LIST_ENTRY(x) x,
#define LIST_END };

LIST_BEGIN
   LIST_ENTRY(1)
   LIST_ENTRY(2)
LIST_END

#19 楼

#20 楼