CODEWITHSUNDEEP
c++
user3893836
user3893836

Reputation: 85

c++ string with extra 0x0?

I have a strange with string with 0x0, can someone help me?

string a = funxx();  // funxx is a external func from Crypto++ libary
string b = "test"

if I print out the content of a and b, they both display as "test"

a.size() is: 5
b.size() is: 4
a.length() is: 5
b.length() is: 4

for( int i = 0; i < a.size(); i++ ) {
    cout << "0x" << hex << (0xFF & static_cast<byte>(a[i])) << " ";
}
print out: 0x74 0x65 0x73 0x74 0x0

for( int i = 0; i < b.size(); i++ ) {
    cout << "0x" << hex << (0xFF & static_cast<byte>(b[i])) << " ";
}
print out: 0x74 0x65 0x73 0x74

My question is, why a.length() and a.size() return 5 instead of 4, and how to make a and b are equal?

Summary: Thanks for lots of replies. I think the problem is clear for me now. The external func from Crypto++ libary return an extra null character in the string, and in string, the length is tracked separately. What I need to do is std::string(a.c_str())

Upvotes: 3

Views: 921

Answers (1)

Mark Ransom
Mark Ransom

Reputation: 308206

A simple way to remove a trailing null from a std::string:

if (!str.empty() && *str.rbegin() == 0)
    str.resize(str.size() - 1);

Upvotes: 1

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