/in/foo.cc: In function 'int main()':
/in/foo.cc:5:21: warning: unused variable 'xunhuan' [-Wunused-variable]
 int x,y,n,c,d,i,j,l,xunhuan,a[101]={0},b[101]={0};
                     ^~~~~~~
/in/foo.cc:36:5: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
 if(d==i&&c==1) {cout<<"(";cout<<a[i];}
    ~^~~