git add之后没有进行更改(Changes not staged after git add)

 您的printf可能已经能够通过'旗帜'自己做到这一点。 不过，您可能需要设置您的语言环境。 下面是我的机器的一个例子： 
 
#include <stdio.h>
#include <locale.h>

int main(void)
{
    setlocale(LC_NUMERIC, "");
    printf("$%'.2Lf\n", 123456789.00L);
    printf("$%'.2Lf\n", 1234.56L);
    printf("$%'.2Lf\n", 123.45L);
    return 0;
}
 
 并运行它： 
 
> make example
clang -Wall -Wextra -Werror    example.c   -o example
> ./example 
$123,456,789.00
$1,234.56
$123.45
 
 该程序的工作方式既可以在我的Mac（10.6.8）上运行，也可以在我试过的Linux机器上运行（Ubuntu 10.10）。 

Your printf might already be able to do that by itself with the ' flag. You probably need to set your locale, though. Here's an example from my machine:
 
#include <stdio.h>
#include <locale.h>

int main(void)
{
    setlocale(LC_NUMERIC, "");
    printf("$%'.2Lf\n", 123456789.00L);
    printf("$%'.2Lf\n", 1234.56L);
    printf("$%'.2Lf\n", 123.45L);
    return 0;
}
 
And running it:
 
> make example
clang -Wall -Wextra -Werror    example.c   -o example
> ./example 
$123,456,789.00
$1,234.56
$123.45
 
This program works the way you want it to both on my Mac (10.6.8) and on a Linux machine (Ubuntu 10.10) I just tried.