movement of 2d object

I was trying to move object by changing velocity

void FixedUpdate()     {         int velocity_x = rb.velocity.x;         int velocity_y = rb.velocity.y;         if(Input.GetKey("a")){             if(velocity_x<0){                              }else if(velocity_x>0){              }             else{                 velocityChange(-1, 0);             }         }else if(Input.GetKey("w")){             if(velocity_y<0){                              }else if(velocity_y>0){              }             else{                velocityChange(0, 1);             }         }else if(Input.GetKey("d")){             if(velocity_x<0){                              }else if(velocity_x>0){              }             else{                 velocityChange(1, 0);             }         }else if(Input.GetKey("s")){             if(velocity_y<0){                              }else if(velocity_y>0){              }             else{                velocityChange(0, -1);             }         }     }      void OnCollisionEnter2D(Collision2D collision){         if(collision.collider.tag =="obstacle"){            Debug.Log("Finish");         }     }     void velocityChange(int velocityX,velocityY){         rb.velocity = new Vector2(velocityX, velocityY);     } 

But, I am getting error.

Assets/movement.cs(57,48): error CS1001: Identifier expected

57 line :

void velocityChange(int velocityX,velocityY){ 

48 line :

} 

40-49 line :

else if(Input.GetKey("s")){         if(velocity_y<0){                      }else if(velocity_y>0){          }         else{            velocityChange(0, -1);         }     }