diff --git a/src/feature.rs b/src/feature.rs
index 65e3885..f29a95c 100644
--- a/src/feature.rs
+++ b/src/feature.rs
@@ -41,4 +41,8 @@ impl Feature {
     pub fn strand(&self) -> char {
         self.strand
     }
+
+    pub fn set_end(&mut self, end: i32) {
+        self.end = end;
+    }
 }
\ No newline at end of file
diff --git a/src/interval.rs b/src/interval.rs
index 2b362d3..7103873 100644
--- a/src/interval.rs
+++ b/src/interval.rs
@@ -107,6 +107,16 @@ impl Interval {
         self.start < end && self.end-1 > start
     }
 
+    // as_ref() returns a reference to the Option's value
+    pub fn name(&self) -> Option<&str> {
+        self.data.as_ref().map(|f| f.name())
+    }
+
+    pub fn set_end(&mut self, end: i32) {
+        self.end = end;
+        self.data.as_mut().map(|f| f.set_end(end));
+    }
+
 }
 
 impl PartialOrd for Interval {
@@ -139,5 +149,3 @@ impl std::fmt::Display for Interval {
         }
     }
 }
-
-
diff --git a/src/intervaltree.rs b/src/intervaltree.rs
index 8d26259..0560792 100644
--- a/src/intervaltree.rs
+++ b/src/intervaltree.rs
@@ -22,6 +22,39 @@ impl IntervalTree {
             for interval in intervals {
                 unique_intervals.insert(interval);
             }
+
+            // merge overlapping intervals with same name
+            use std::collections::HashMap;
+
+            // Create a HashMap where the keys are the names of the intervals and the values are vectors of intervals with that name.
+            let mut grouped_intervals: HashMap<String, Vec<Interval>> = HashMap::new();
+            for interval in &unique_intervals {
+                grouped_intervals.entry(interval.name().unwrap().to_string()).or_insert(Vec::new()).push(interval.clone());
+            }
+
+            // For each name in the HashMap, sort the intervals by their start position and then merge the overlapping intervals.
+            for intervals in grouped_intervals.values_mut() {
+                intervals.sort_by(|a, b| a.start.cmp(&b.start));
+                let mut i = 0;
+                while i < intervals.len() - 1 {
+                    if intervals[i].end >= intervals[i+1].start && intervals[i+1].end >= intervals[i].end {
+                        intervals[i].end = intervals[i+1].end;
+                        intervals.remove(i+1);
+                    } else {
+                        i += 1;
+                    }
+                }
+            }
+
+            // Create a new HashSet of intervals from the merged intervals.
+            let mut unique_intervals: HashSet<Interval> = HashSet::new();
+            for intervals in grouped_intervals.values() {
+                for interval in intervals {
+                    unique_intervals.insert(interval.clone());
+                }
+            }
+
+
             // convert to vector
             //let unique_intervals: Vec<Interval> = unique_intervals.into_iter().collect();
             //eprintln!("filtered intervals");
@@ -91,6 +124,7 @@ impl IntervalTree {
         }
     }
 
+
     pub fn add(&mut self, interval: Interval) {
         if interval.is_null() {
             panic!("IntervalTree: Null Interval objects are not allowed in IntervalTree");
@@ -300,8 +334,7 @@ impl IntervalTree {
     }
 
     pub fn contains(&self, start: i32, end: i32) -> Vec<&Interval> {
-        let mut result = self.overlap(start, end);
-        // TODO: merge overlapping intervals with same name into one interval
+        let mut result: Vec<&Interval> = self.overlap(start, end);
         result.retain(|x| x.start <= start && x.end >= end);
         result
     }
diff --git a/src/main.rs b/src/main.rs
index c5d9bbb..526e502 100755
--- a/src/main.rs
+++ b/src/main.rs
@@ -244,7 +244,6 @@ struct Args {
     _m: String,
 
     // Stranded
-    // TODO: implement stranded mode
     #[structopt(
         short = "s",
         long = "stranded",
@@ -363,17 +362,17 @@ fn prepare_count_hashmap(gtf: &Vec<Option<IntervalTree>>) -> HashMap<String, f32
     }
 
     // Add the special keys
-    counts.insert("__no_feature".to_string(), 0 as f32);
-    counts.insert("__ambiguous".to_string(), 0 as f32);
-    counts.insert("__not_aligned".to_string(), 0 as f32);
-    counts.insert("__too_low_aQual".to_string(), 0 as f32);
-    counts.insert("__alignment_not_unique".to_string(), 0 as f32);
+    counts.insert("__no_feature".to_string(), 0f32);
+    counts.insert("__ambiguous".to_string(), 0f32);
+    counts.insert("__not_aligned".to_string(), 0f32);
+    counts.insert("__too_low_aQual".to_string(), 0f32);
+    counts.insert("__alignment_not_unique".to_string(), 0f32);
     counts
 }
 
 fn read_gtf(file_path: &str, feature_type_filter: &str, ref_names_to_id: &HashMap<String, i32>) -> Vec<Option<IntervalTree>> {
     let mut map: HashMap<i32, Vec<Interval>> = HashMap::new();
-    let file = File::open(file_path).expect("Kan het bestand niet openen");
+    let file = File::open(file_path).expect("Could not open this file");
     let mut reader = BufReader::new(file);
     let mut counter = 0;
     let mut line = String::new();
@@ -691,6 +690,7 @@ fn process_intersection_nonempty_read(_features: &IntervalTree, _start_pos: i32,
 fn process_intersection_strict_read(features: &IntervalTree, start_pos: i32, end_pos: i32, strand: bool, overlapping_features: &mut Vec<Feature>, args: &Args) {
     //todo!("process_partial_read for intersection-strict");
     let new_contained = features.contains(start_pos, end_pos);
+    // change new_contained to a Vec<&Interval>
     let strand = if strand { '-' } else { '+' };
     // add all contained features to the list
     add_stranded_features(new_contained, strand, overlapping_features, args);