Added add function

main.zig

@@ -15,17 +15,23 @@ fn Vec3(comptime T: type) type {
         }
         
         fn print(this: Self) !void {
-            try writer.print("X: %d\nY: %d\nZ: %d\n", .{this.x, this.y, this.x});
+            try writer.print("X: {d}\nY: {d}\nZ: {d}\n", .{this.x, this.y, this.z});
         }
         
-        //fn add(this: *Self, other: Self) {
-        //    
-        //} 
+        fn add(this: *Self, other: Self) void {
+            this.x = this.x + other.x;
+            this.y = this.y + other.y;
+            this.z = this.z + other.z;
+        } 
     };
 }
 
 pub fn main() !void {
     var vec1: Vec3(u64) = undefined;
+    var vec2: Vec3(u64) = undefined;
     vec1.init(2, 4, 3);
-    vec1.print();
+    vec2.init(1, 1, 1);
+    try vec1.print();
+    vec1.add(vec2);
+    try vec1.print();
 }