C++

Forum

 
 
How to Store the Last Data ?

geezle86 (36)
Case

An automotive company needs a program that checks gasoline usages. This program can be used to check the gasoline usages based on how fast the car move. As a programmer, you are asked to create the program. Here are some rules about the program:

• At the beginning, the program will set the gasoline to 100 liters.

• Show the main menus, such as:
1. Start Driving
2. Rest
3. Exit

• If user chooses “Start Driving”, then the program will:
o Show the speed (km/hour) with random 1 – 100.
o If speed is less than 50 km/hour, gasoline will be reduced by 20 liters.
o If speed is equals or larger than 50 km/hour, gasoline will be reduced by 40 liters.
o If the gasoline is empty, then the program will show “Your gasoline is not enough to run the car…”

• If user chooses “Rest”, then the program will:
o If the gasoline is full, then the program will show “Your gasoline is full…”, else the gasoline will be increased by 20 liters.

• If user chooses “Exit”, then the program will end.



My attempt: 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
 
#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
    int gasoline = 100;
    int menu;
    char returnMainmenu;

    do
    {
        do
        {
            cout << "1. Start driving" << endl << "2. Rest" << endl << "3. Exit" << endl << endl;
            cout << "What do you want to do: ";
            cin >> menu; cout << endl;
        }
        while(menu<1 || menu>3);

        if(menu == 1)
        {
            int speed = rand() % 100 + 1;
            cout << "Your speed: " << speed << endl;

            if(speed >= 50)
            {
                cout << "Current fuel: " << gasoline-40 << endl;
                cout << "Keep moving [Y/N]: "; cin >> returnMainmenu; cout << endl;
            }

            else
            {
                cout << "Current fuel: " << gasoline-20 << endl;
                cout << "Keep moving [Y/N]: "; cin >> returnMainmenu; cout << endl;
            }

        if(menu == 2)
        {
            if(gasoline < 100)
            {
                gasoline+20;
                cout << "Fuel added, current fuel: " << gasoline << endl;
                cout << "Keep moving [Y/N]: "; cin >> returnMainmenu; cout << endl;
            }

            if(gasoline==100)
            {
                cout << "Your fuel is full." << endl;
                cout << "Keep moving [Y/N]: "; cin >> returnMainmenu; cout << endl;
            }
        }

        if(menu==3)
        {
            cout << "Goodbye, have a nice day!" << endl;
        }

        }
    } while(returnMainmenu=='y');

    return 0;
}


My problem is:

Example, i choose menu 1, lets say gasoline reduced into 60. Then back to main menu, and choose 2. BUT THE GASOLINE STILL 100 not 60 :(

How to store the last gasoline so we can use it for another menu (like rest)? Thanks
Last edited on
giblit (3750)
Shouldn't line 20 be && not ||?
Also you are not assigning values to gasoline on line 29 and 35. You are just outputting a number subtracting a number if you want to assign a value you will use -= that will subtract then asign the new value. gasoline -= 20; Same thing goes with line 43 you are not assigning the new value you need += instead of +.

I might suggest you read up on operators a bit more. Especially assignment( = )
http://www.cplusplus.com/doc/tutorial/operators/
geezle86 (36)
Oh my god, I LOVE YOU SO MUCH giblit :* Thanks :)
Topic archived. No new replies allowed.