我正在尝试创建一个菜单，但我的代码一直在循环

Question

I'm trying to create a menu where the user picks a number to execute a function but my code keeps looping. My 2d array keeps looping statements even outside of the for loop. I found a way to stop the loop with

        cout << endl;
        cout << "Enter another number or press -1 to exit: ";
        cin >> userNum; 

But then I tested it with a simple cout statement (usernum ==3 section) and that loops too. I'm not sure what I'm doing wrong? I think it has to do with my while loop but I'm not sure. I would appreciate any help!!

     #include <iostream>
     #include <string>
     #include <ctime>
     using namespace std;
     // function #1, finds the minimum value in a array
     int findMin(int a[], int size){
int i;
int min;
min = a[0];
for (i = 1; i < size; ++i) {
    if(min > a[i]){
            min = a[i];
    }
}
return min;
} 
 // will write other functions later
int main()
{
int userNum = 0;
int arraySize = 4;
int array[arraySize];
int i;
int j;

int rowSize = 3;
const int colSize = 4;
int array2[rowSize][colSize];

cout << "MENU" << endl;
cout << "-1: exit" << endl;
cout << "1: minimum value of integer array" << endl;
cout << "2: computes the average of all elements in a 2D array" << endl;
cout << "3: Is it a leap year?" << endl;
cout << "4: calculates addition, subtraction, multiplation, divison" << endl;
cout << "5: read a text file and store each word into a vector of string" << endl;
cout << "6: count the frequency of each word" << endl;

ll

cout << "7: remove all the stop words from words" << endl;
cout << "Please input a number from the menu:" << endl;
cin >> userNum;

while (userNum != -1) {

    if (userNum == 1) {

        cout<<"Enter 4 array elements: ";
            for(i=0; i< arraySize; i++){
                cin>>array[i];
            }
        cout << "minimum value of integer array: " << findMin(array, arraySize) << endl;
        cout << "Enter another number or press -1 to exit: ";
        cin >> userNum;
    }

    else if (userNum == 2) {
        cout << "here are the elements in the 2d array.";

        for (i=0; i < rowSize; i++ ){
            cout<< endl;
            for (j =0; j < colSize; j=j+1){
                array2[i][j] = 1+(rand()%9);
                cout << array2[i][j] << " ";
            }
    }
        cout << endl;
        cout << "Enter another number or press -1 to exit: ";
        cin >> userNum;
    }

    else if (userNum == 3){
        cout << "hahah" << endl;
    }

l

     else {
        cout << "Enter another number or press -1 to exit: ";
        cin >> userNum;
    }
}
cout << "exited";
return 0;
}

Answer 1

Your userNum == 3 case does not read in a new userNum , so that is why it loops. Once userNum is 3 it never changes again.

One way to fix it is to move your "get user input" code into a separate function, and then just call that at the end of your loop. That way you don't have to repeat code all over the place, and you don't forget to add it when you implement a new case.

Something like this:

int getMenuItem()
{
    cout << "MENU" << endl;
    cout << "-1: exit" << endl;
    cout << "1: minimum value of integer array" << endl;
    cout << "2: computes the average of all elements in a 2D array" << endl;
    cout << "3: Is it a leap year?" << endl;
    cout << "4: calculates addition, subtraction, multiplation, divison" << endl;
    cout << "5: read a text file and store each word into a vector of string" << endl;
    cout << "6: count the frequency of each word" << endl;
    cout << "7: remove all the stop words from words" << endl;
    cout << "Please input a number from the menu:" << endl;
    int input;
    cin >> input;
    return input;
}

int main()
{
    ...
    userNum = getMenuItem();  // <- Before the loop, to get the initial selection

    while (userNum != -1) {
        if (userNum == 1) {
            ...
        }
        else if (userNum == 2) {
            ...
        }
        else if (userNum == 3) {
            ...
        }

        userNum = getMenuItem();  // <- At the end of the loop, to get the next
    }
    cout << "exited";
    return 0;
}