How can I use the following vector to read true/false from using a while or for loop. With this implemtation of the loop I get an error for the oprator !=

no operator "!=" matches these operands

vector<bool> Verification;

Verification.push_back(true);
Verification.push_back(false);
Verification.push_back(true);
Verification.push_back(false);
Verification.push_back(true);

for (int it = Verification.begin(); it != Verification.end(); it  ) {   
                    if (it==true) cout<<"true";
                    else if (it == false) cout<<"false";
}

CodePudding user response：

You are declaring it as the wrong type. The result of Verification.begin() is a std::vector<bool>::iterator. But you don't need to specify that.

Use a range-for loop instead

for (bool b : Verification) 
{
    std::cout << std::boolalpha << b;
}

CodePudding user response：

There are various ways to iterate over an std::vector

1. Using iterator

Long example:

for( std::vector<bool>::iterator it = v.begin(); it != v.end();   it ) std::cout << *it;

or the same but shorter:

for( auto it = v.begin(); it != v.end();   it ) std::cout << *it;

2. Using index

Here:

for( unsigned int i = 0; i != v.size();   i ) std::cout << v[i];

3. Range loop

Here:

for( bool b : v ) std::cout << b;

(there are some more but we will omit them for clarity)

Looks like you mixed 1 and 2 hense you have compilation errors. Choose one.

CodePudding user response：

The problem is that Verification.begin() gives you an iterator while it is an int.

To solve this you could modify your for loop to:

for (std::vector<bool>::iterator it = Verification.begin(); it != Verification.end(); it  ) {   
                    if (*it==true) cout<<"true";
                    else if (*it == false) cout<<"false";
}

Note *it means we're dereferencing the iterator it and then comparing the result.

Also you don't need the else if because you can just use else.

Alternative solution

You can also use a range-base for loop as shown below:

for (bool element : Verification) 
{
    std::cout << std::boolalpha << element;
}