okay i decided to take a different approach with globals instead of pointers. It compiles, but the screen is black. Any input in this case?

Code:

int menu();
int addition(int reward); // function to return truth values
int subtraction(int reward);

int main()
{



int Result, Finished = 0;
int choice, score = 0;
int reward = 0;

while(Finished != 1); // while finished is not true
{
    printf("\nscore: %d", score); // print the score



{
choice = menu(); // calls for user input and enters it to switch





    switch  (choice){ // accesses the functions
            case 0: Finished = 1;                     break;
            case 1: Result = addition(reward);           break;
            case 2: Result = subtraction(reward);        break;
            default : printf("Error in input\n\n");      break;
    }
    if(Result == 1){
        score += reward; // score = score + reward
        }

}
}
}
int menu() //main menu that gets called and allows fr user input
{
    int MenuChoice;
        printf("\n");
        printf("Enter 1 for addition\n");
        printf("Enter 2 for Subtraction\n");
        printf("Enter 0 to quit\n");
        printf("-----------------\n");
        printf("Choice: ");
    scanf("%d", &MenuChoice); // user input
    return MenuChoice; //return the choice to choice to select a case
}



int addition(int reward) //function that is called by the users selection
{

int answer;
int random1, random2;



srand(time(NULL)); //generates fresh numbers each time.

    random1 = 1+(rand()%99); // from 1-99
    random2 = 1+(rand()%99); // from 1-99


    printf("\n%d - %d = ", random1, random2); //code to format the random math problem
    scanf("%d", &answer); // user input of answer
{




if (answer == (random1+random2)){
        printf("Congratulations\n\n");
            return reward = 1;// tellsesult whether to add a pt or not
        }   //if user is correct than the score is incremented
    else{
        printf("Incorrect\n\n");} //if not than the score is not incremented
return 0;


}
}



int subtraction(int reward) // follows same model as previous function, but instead subtraction.
{


    int answer;
    int random1, random2;




srand(time(NULL));

    random1 = 1+(rand()%99); // from 1-99
    random2 = 1+(rand()%99); // from 1-99



    printf("\n%d - %d = ", random1, random2);
    scanf("%d", &answer);


    if (answer == (random1-random2)){
        printf("Congratulations\n\n");
            return reward = 1;// tells result whether to add a pt or not
        }
        else{
            printf("Incorrect\n\n");}

return 0;

}