diff --git a/src/func_plot.rs b/src/func_plot.rs
index eecbe38..62f17e6 100644
--- a/src/func_plot.rs
+++ b/src/func_plot.rs
@@ -57,29 +57,32 @@ pub fn draw(
 fn integral_rectangles(
     min_x: f32, step: f32, num_interval: usize, func: &dyn Fn(f64) -> f64,
 ) -> (Vec<(f32, f32, f32)>, f32) {
-    let data2: Vec<(f32, f32, f32)> = (0..num_interval).map(|e| {
-        let x: f32 = ((e as f32) * step) + min_x;
+    let data2: Vec<(f32, f32, f32)> = (0..num_interval)
+        .map(|e| {
+            let x: f32 = ((e as f32) * step) + min_x;
 
-        let x2: f32 = match x > 0.1 {
-            true => x+step,
-            false => x-step,
-        };
+            let x2: f32 = match x > 0.1 {
+                true => x + step,
+                false => x - step,
+            };
 
-        let tmp1: f32 = func(x as f64) as f32;
-        let tmp2: f32 = func(x2 as f64) as f32;
+            let tmp1: f32 = func(x as f64) as f32;
+            let tmp2: f32 = func(x2 as f64) as f32;
 
-        let y: f32 = match tmp2.abs() > tmp1.abs() {
-            true => tmp1,
-            false => tmp2
-        };
+            let y: f32 = match tmp2.abs() > tmp1.abs() {
+                true => tmp1,
+                false => tmp2,
+            };
 
-        // Add current rectangle's area to the total
-        if !y.is_nan() {
-            (x, x2, y)
-        } else {
-            (0.0, 0.0, 0.0)
-        }
-    }).filter(|ele| ele != &(0.0, 0.0, 0.0)).collect();
-    let area: f32 = data2.iter().map(|(_, _, y)| y*step).sum(); // sum of all rectangles' areas
+            // Add current rectangle's area to the total
+            if !y.is_nan() {
+                (x, x2, y)
+            } else {
+                (0.0, 0.0, 0.0)
+            }
+        })
+        .filter(|ele| ele != &(0.0, 0.0, 0.0))
+        .collect();
+    let area: f32 = data2.iter().map(|(_, _, y)| y * step).sum(); // sum of all rectangles' areas
     return (data2, area);
 }