break exit what?

[kenneth6]

string name="peter@#%#(*pen";
 
int i=0;
while(name.c_str()[i])
{
    if (ispunct(name.c_str()[i]))
    {
        cout << "Name not correct!" << endl;
        break;
    }
    i++;
}

I want to confirm if the "break;" line exit the if-statement or the while loop.
which one is correct?

if there are more while loop outside the while loop written above, which does the break; line refer to?

are there any other ways that i can use ispunct function for string type data?

[Ganon11]

I want to confirm if the "break;" line exit the if-statement or the while loop.
which one is correct?

The break statement exits the 'most current' loop block. In your example, that is the while loop.

if there are more while loop outside the while loop written above, which does the break; line refer to?

The break statement will exit the innermost loop. For example:

while (condition1) {
   while (condition2) {
      if (condition3) {
         cout << "If statement." << endl;
         break;
      }
      cout << "End of loop2." << endl;
   }
   cout << "End of loop1." << endl;
}

In this code, if the break statement is reached, "End of loop2" will not print, because the rest of the body of the second loop is skipped. But the first loop is not affected, and prints "End of loop1." before continuing (if condition1 is true, of course).

are there any other ways that i can use ispunct function for string type data?

You can actually just say:

ispunct(myString[i])

The STL string class has overloaded the square bracket operators to return the character at the specified position, as if it were a character array.

[kenneth6]

You can actually just say:

ispunct(myString[i])

The STL string class has overloaded the square bracket operators to return the character at the specified position, as if it were a character array.

string name="peter@#%#(*pen";
int i=0;
while(name.c_str()[i])
{
    if (ispunct(name[i]))
    {
        cout << "Name has punct!" << endl;
        break;
    }
    i++;
}

Do you mean I can check like this? but what is the condition in the while loop ?

[Natasha26]

string name="peter@#%#(*pen";
int i=0;
while(name.c_str()[i])
{
    if (ispunct(name[i]))
    {
        cout << "Name has punct!" << endl;
        break;
    }
    i++;
}

Do you mean I can check like this? but what is the condition in the while loop ?

Actually, u can modify the while(...) test too. Use while(name[i]), when the end of string is reached, name[n-1] will return '\0' which just evaluates to false and the while loop exits, either that or the if(...) test will take care of the exit when it encounters a punctuation character.

[Ganon11]

You should probably be using a for...loop:

for (int i = 0; i < name.length(); i++) {
   // Loop body here.
}

I'm not entirely sure if std::string terminates its character array with a '\0'.

[Natasha26]

Good point! In my defence though, he used a string literal ("...") and those are null-terminated, so when reached, the while will loop will evaluate to false.

[hsn]

for your code the bread will break you while loop
if you had

while(){

while(){

while(){
break;
}}}

the third while will break