This is my snippet of segment tree implementation with lazy propagation. Hope this will help you.
#define int long long
#define MAX 100005*3
int stree[MAX],lazy[MAX];
void update(int cur,int cur_lft,int cur_rgt,int st,int en,int val)
{
if(cur_lft>en || cur_rgt<st) return ;
if(cur_lft>=st && cur_rgt<=en)
{
stree[cur]+=val*(cur_rgt-cur_lft+1);
lazy[cur]+=val;
return;
}
int l=cur<<1,r=(cur<<1)+1,mid=(cur_lft+cur_rgt)>>1;
update(l,cur_lft,mid,st,en,val);
update(r,mid+1,cur_rgt,st,en,val);
stree[cur]=stree[l]+stree[r]+lazy[cur]*(cur_rgt-cur_lft+1);
}
int query(int cur,int cur_lft,int cur_rgt,int st,int en,int lzy)
{
if(cur_lft>en || cur_rgt<st) return 0;
if(cur_lft>=st && cur_rgt<=en) return stree[cur]+lzy*(cur_rgt-cur_lft+1);
int l=cur<<1,r=(cur<<1)+1,mid=(cur_lft+cur_rgt)>>1;
int left_tree=query(l,cur_lft,mid,st,en,lzy+lazy[cur]);
int right_tree=query(r,mid+1,cur_rgt,st,en,lzy+lazy[cur]);
return left_tree+right_tree;
}
Edit To update and query into segment tree we can call following functions:
query(1,0,n-1,lower_range,upper_range,0));
update(1,0,n-1,lower_range,upper_range,v);