Breaking out of nested loops in C++ [duplicate]

Answer 1

You could build in a variable check in the outer loop, lets say:

bool end;

In the inner loop, at some point, you want to break out and set end to true. You also need a if-condition.

Answer 2

You could extract the loops out to a separate function and use return.

void doTheLoop(int n, int m) {
    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
             if (some condition) {
                 // Do something and break...
                 return;
             }
        }
    }
}

doTheLoop(n, m);
//blablabla ...

Answer 3

Use another int variable.

for (int i = 0, Out = 0; i < m && Out == 0; i++) {
    for (int j = 0; j < n && Out == 0; j++) {
         if (some condition) {
             Out = 1;
         }
    }
}

Answer 4

For example

for ( int i = 0; i < m; i++ ) 
{
    bool exit = false;

    for ( int j = 0; !exit && j < n; j++ ) 
    {
         if ( ( exit = some condition ) ) 
         {
             // Do something and break...
         }
    }

    if ( exit ) break;
}

Or

bool exit = false;

for ( int i = 0; !exit && i < m; i++ ) 
{
    for ( int j = 0; !exit && j < n; j++ ) 
    {
         if ( ( exit = some condition ) ) 
         {
             // Do something and break...
         }
    }
}

Answer 5

You can use "goto" for this purposes.

Answer 6

"Go directly to [...]" sound like a perfect job for goto. And it is !

for (int i = 0; i < m; i++) {
    for (int j = 0; j < n; j++) {
         if (some condition) {
             // Do something and break...
             goto afterLoop; // Breaks out of both loops
         }
    }
}
afterLoop:
// More stuff