字符串比较中的std :: out_of_range异常

Question

I am trying to use compare function of std::string. Here is my code:

int main() {
    string str1 = {"apple"};
    vector<string> vec1 = {"apple"};
    string suffix = {"le"};

    if (str1.compare(str1.size() - suffix.length(), suffix.length(), suffix) == 0)
        cout << "Yes!!" << endl;         // This prints

    if (vec1[0].compare(vec1[0][vec1[0].size() - suffix.length()], suffix.length(), suffix) == 0)
        cout << "Yes-1!!" << endl;       // This doesn't
}

The output is:

Yes!!
terminate called after throwing an instance of 'std::out_of_range'
what():  basic_string::compare: __pos (which is 108) > this->size() (which 
is 5)
Aborted (core dumped)

Need some help figuring out what am I doing wrong. Thanks.

Answer 1

I've changed your second call to compare() to this:

if (vec1[0].compare(vec1[0].size() - suffix.length(), suffix.length(), suffix) == 0)

as it was unclear what you we're trying to accomplish in the original call.

This is the full code that works without throwing an error:

#include <string>
#include <vector>
#include <iostream>

using namespace std;

int main() {
    string str1 = {"apple"};
    vector<string> vec1 = {"apple"};
    string suffix = {"le"};

    if (str1.compare(str1.size() - suffix.length(), suffix.length(), suffix) == 0)
        cout << "Yes!!" << endl;         // This prints

    if (vec1[0].compare(vec1[0].size() - suffix.length(), suffix.length(), suffix) == 0)
        cout << "Yes-1!!" << endl;       // This doesn't
}

Also, beware of posting with typos in the code, as the comment on the question already noted.