You are trying to pass the address of the variable mileage:
That is not what you want. Pass the variable as an argument, without the & operator. Also, you will want to have a format specifier in the call to printf(), which you did not supply.Code:printf("The miles per gallon for this tank was " , &mileage);
Code:printf("The miles per gallon for this tank was %d" , mileage);