How do I resolve this error: jump to case label crosses initialization [duplicate]

Question

I have the following error in my Calculator code and do not understand how to correct it. Please any advice would be helpful.

ERROR: error: jump to case label [-fpermissive]| error:crosses initialization of 'int sum'| error: 'exit' was not declared in this scope|

CODE:

#include <iostream> #include <cmath> using namespace std;          void display_menu();  int get_menu_choice(); void get_two_numbers(int &a, int &b); int add(int a, int b); int subtract(int a, int b);   int main()  {  int choice;    do    {     display_menu();     choice = get_menu_choice();     int x, y;     switch (choice)     {         case 1: get_two_numbers(x, y);                 int sum = add(x, y);                 cout << x << " + " << y << " = " <<  sum << endl;                 break;         case 2: get_two_numbers(x, y);                 int diff = subtract(x, y);                 cout << x << " - " << y << " = " <<  diff << endl;                 break;         default:;     }       } while (choice != 3);       cout << "Good bye...now." << endl;       return 0;        }    void display_menu()   {    cout << endl;    cout << "Simple Calculator Menu" << endl;    cout << "----------------------" << endl;    cout << " 1. Addition (+) " << endl;    cout << " 2. Subtraction (-) " << endl;    cout << " 3. Quit to exit the program" << endl;    cout << endl;   }   int get_menu_choice()   {    int choice;    cout << "Enter your selection (1, 2, or 3): ";    cin >> choice;    while(((choice < 1) || (choice > 3)) && (!cin.fail()))    {     cout << "Try again (1, 2, or 3): ";     cin >> choice;     }   if (cin.fail())     {       cout << "Error: exiting now ... " << endl;       exit(1);      }    return choice;     }   void get_two_numbers(int &a, int &b)   {     cout << "Enter two integer numbers: ";     cin >> a >> b;   }    int add(int a, int b)   {    return (a + b);   }   int subtract(int a, int b)   {     return (a - b);   } 

Answer 1

You are declaring new variables inside a case statement without creating an enclosing scope:

switch (choice) {     case 1: get_two_numbers(x, y);             //* vv here vv *             int sum = add(x, y);             //* ^^ here ^^ */             cout << x << " + " << y << " = " <<  sum << endl;             break;     case 2: get_two_numbers(x, y);             //* vv here vv */             int diff = subtract(x, y);             //* ^^ here ^^ */             cout << x << " - " << y << " = " <<  diff << endl;             break;     default:; } 

Here's how to fix it:

switch (choice) {     case 1:         {             get_two_numbers(x, y);             int sum = add(x, y);             cout << x << " + " << y << " = " <<  sum << endl;         }         break;     case 2:         {             get_two_numbers(x, y);             int diff = subtract(x, y);             cout << x << " - " << y << " = " <<  diff << endl;         }         break;     default:         break; } 

Of course, the exact formatting of brackets and indentation is up to you.

Answer 2

A "case" of a switch doesn't create a scope, so, as the error says, you're jumping over the initialization of "sum" if the choice isn't 1.

You either need to declare sum and diff outside the switch, or create blocks with { } for each of the cases.