java - How do you call a method with parameters from main method if statement? -

i trying call method gascost main method. give user choice of entering number bring calculation, in instance user has selected option 3. integer gallons_gas defined in main method, passing gascost method.

i error after else statement , can't compile. says .class expected variable name gallons_gas starts , after gallons_gas says ; expected. doing wrong , how fix this?

public class deryck_hw2_tripcalculatormenu  

{

public static void main(string[] args) {     //get scanner instance     scanner userinput = new scanner(system.in);      //ask gallons of gas consumed     system.out.print("gallons of gas consumed: ");      //save gallons of gas consumed     int gallons_gas = userinput.nextint();      //give user options menu     menu();      //ask user choice     system.out.print("choose options above (enter number 1-4): ");      //get user choice 1-4     int choice = userinput.nextint();      //test choice     if (choice == 1)     {         //avgspeed();     }         else if (choice == 2)     {         //mpg();     }         else if (choice == 3)     {         gascost(int gallons_gas);     }        else     {         system.out.print("error: selection invalid. restart program , enter number between 1 , 4.");     }     }   public static void gascost(int gallons_gas) {     //get scanner instance     scanner userinput = new scanner(system.in);      //ask cost of gallon of gas     system.out.print("what cost per gallon of gas? ");      //save cost per gallon     double gallon_cost = userinput.nextdouble();      //calculate total cost     double total_cost = (gallons_gas * gallon_cost);      system.out.print("total cost of gas trip $" + total_cost);  } 

gascost(int gallons_gas); 

should be

int gallons_gas; if (...) {     gascost(gallons_gas); } 

you cannot declare int within parameter list of method call.