foo.cc: In function ‘int main()’:
foo.cc:6:22: warning: ‘n’ is used uninitialized [-Wuninitialized]
    6 |         for(int i=1;i<=n;i++){
      |                     ~^~~
foo.cc:5:13: note: ‘n’ was declared here
    5 |         int n,a[maxn],ans=0;
      |             ^
foo.cc:11:44: warning: ‘a’ may be used uninitialized [-Wmaybe-uninitialized]
   11 |                                 if(a[j]+a[k]==a[i]){
      |                                         ~~~^
foo.cc:5:15: note: ‘a’ declared here
    5 |         int n,a[maxn],ans=0;
      |               ^