Fix C++ Break Invalid Statement Error

In C++, the break statement is often used in loops or switch statements to exit the current loop or switch statement.

If you find that the break statement is not working in C++, it may be due to a few reasons:

1. The break statement is not used within a loop or switch statement: Make sure your break statement is used within a loop or switch statement, otherwise it will be invalid.
2. Nested loops or switch statements: If you use a break statement within nested loops or switch statements, it will only exit the current inner loop or switch statement. If you want to exit the outer loop or switch statement, you can use labels and goto statements.
3. Forgetting to include the “break” statement: in a switch statement, if you forget to include the “break” statement at the end of each case statement, the program will continue executing the next case statement until it encounters a “break” statement or reaches the end of the switch statement.

Here is an example code demonstrating the use of labels and goto statements to break out of an outer loop or switch statement within nested loops or switch statements.

#include <iostream>
using namespace std;

int main() {
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            if (i == 1 && j == 1) {
                goto end; // 跳转到标签end
            }
            cout << i << ", " << j << endl;
        }
    }
    
    end: // 定义标签end
    cout << "End of loop" << endl;
    
    return 0;
}

In the sample code above, if i is equal to 1 and j is equal to 1, the goto statement will be used to jump to the label “end” and exit the outer loop.

Please be aware that using the goto statement can lead to poor code readability, so it is recommended to avoid using it in most cases. If possible, use other control flow statements to achieve the same purpose.