如何在C++中的循环外使用For循环中的变量

所以我的编程技能有点生疏，除了过去上过的大学课程外，没有任何现实世界的经验。我正在为一个班编写一个程序，但遇到了一个障碍；我不知道如何在循环外的For循环中使用变量的值。这是我引用的代码：

#include "iostream"
using namespace std;
int want, have, need;
int counter = 0;
char response, cont;
int diff(int want, int have);
int main(){
cout << "Welcome!n";
cout << "This program will help you reach your money saving goals!n";
cout << "Would you like to use this program? (y/n)n";
    cin >> response;
    while (response == 'y'){
        cout << "Please enter all amounts in whole dollars only!n";
        cout << "Please enter the amount of money you would like to have saved: $";
        cin >> want;
        cout << "nPlease enter the amount of money you currently have saved: $";
        cin >> have;
        if (have >= want){
            cout << "You have already reached or exceeded your goal, this program will not be able to help you!n";
            system("Pause");
            return 0;
        }
        cout << "nYou need to save $" << diff(want, have) << " more money to reach your goal!n";
        cout << "Would you like me to help you with a savings plan?";
        cin >> cont;
        while (cont == 'y'){
            int menu;
            cout << "Please select from the following options: n";
            cout << "1 - Daily Saving Plann";
            cout << "2 - Weekly Saving Plann";
            cout << "3 - Monthly Saving Plann";
            cout << "Enter the number associated with your choice: n";
            cin >> menu;
            switch (menu){
                case 1: {
                    int daily;
                    cout << "You have chosen the Daily Savings Plann";
                    cout << "How much money can you save every day? $";
                    cin >> daily;
                    for (int x = daily; x < need; x++){
                        daily = daily + daily;
                        counter++;
                    }
                    cout << "nIt will take you " << counter << " days to reach your goal!n";
                    break;
                }
                case 2: {
                    int weekly;
                    cout << "You have chosen the Weekly Savings Plann";
                    cout << "How much money can you save every week? $";
                    cin >> weekly;
                    for (int x = weekly; x < need; x++){
                        counter++;
                    }
                    cout << "nIt will take you " << counter << " weeks to meet your goal!n";
                    break;
                }
                case 3: {
                    int monthly;
                    cout << "You have chosen the Monthly Savings Plann";
                    cout << "How much money can you save every month? $";
                    cin >> monthly;
                    for (int x = monthly; x < need; x++){
                        monthly = monthly + monthly;
                        counter++;
                    }
                    cout << "nIt will take you " << counter << " months to reach your goal!n";
                    break;
                }
                default: cout << "You made an invalid selection";
                    cout << "Would you like to look at a different saving plan? (y/n)n";
                    cin >> cont;
            }
        }
    }
}
int diff(int want, int have){
return want - have;
}

所以，当我运行程序时，一切都正常，但计数器的值在最后的cout语句中总是显示为"0"。

我理解它为什么这么做，我想。。这是因为循环外的"int counter=0"声明，所以我假设它在循环退出后会返回到那个值。

如果我不初始化计数器变量，我会得到一个错误，如果我在循环中声明该值，我会在尝试在cout语句中使用它时得到一个误差，就像上面所说的那样。

我甚至不确定我的for循环结构是否正确。。。基本上，我希望它添加到自己的每周变量，直到x = need的总和。我还想捕捉它需要多少次迭代，然后将其输出为周数。希望这一切都有意义；感谢您的任何帮助。