Cracking the Coding Interview 8.5

Implement an algorithm to print all valid combinations of n-pairs of parentheses

#include<stdio.h>

void f(int idx,int left,int right,char *buf)
{
    if(left ==  && right == )
    {
        buf[idx] = '\0';
        printf("%s\n",buf);
    }
    if(left>)
    {
        buf[idx]='(';
        f(idx+,left-,right,buf);
    }
    if(right>left)
    {
        buf[idx]=')';
        f(idx+,left,right-,buf);
    }
}

int main()
{
    int n=;
    char *buf = new char[n+];
    f(,n,n,buf);
    return ;
}