poj 1488 TEX Quotes

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>using namespace std;int main(){    char ch;    bool first = true;    while ((ch = getchar()) != EOF)    {        if (ch == '"')        { if (first) {     printf("``");     first = false; }else {     printf("''");     first = true; }        }else        { putchar(ch);        }    }    return 0;}