regex in C/C++

regex.cpp

#include <stdio.h>
#include <sys/types.h>
#include <regex.h>
int main(int argc,char** argv)
{
    int status,i;
    int cflags=REG_EXTENDED;
    regmatch_t pmatch[1];
    const size_t nmatch=1;
    regex_t reg;
    const char *pattern ="^\\w(\\.?\\w)+@\\w+(\\.\\w+)*\\.[A-Za-z]+$";
    char buf[256];

    regcomp(&reg, pattern,cflags);
    while(scanf("%s", buf)!=EOF)
    {
        if((status=regexec(&reg,buf,nmatch,pmatch,0))==0)
        {
            printf("YES\n");
            regfree(&reg);
        }
        else
        {
            printf("NO\n");
        }
    }
    return 0;
}