C++ 相当于 Java StringUtils.indexOfDifference

Question

对于 C++20，是否有与 Java 的 StringUtils.indexOfDifference() 等效的库？

比较两个大字符串并确定它们不同之处的有效方法是什么？

Answer 1

您可以使用 <algorithm>

中的 std::mismatch

Returns the first mismatching pair of elements from two ranges

例如

#include <algorithm>
#include <iostream>
#include <iterator>
#include <string>

std::size_t IndexOfDifference(std::string const& lhs, std::string const& rhs) {
    auto diff = std::mismatch(lhs.begin(), lhs.end(), rhs.begin());
    return std::distance(lhs.begin(), diff.first);
}

int main() {
    std::cout << IndexOfDifference("foobar", "foocar");
}

会output

Answer 2

如果您注意导致结果中出现结束迭代器的不同情况，则可以使用 std::mismatch：

#include <algorithm>
#include <string>
#include <iterator>
#include <iostream>

void mism(const std::string& a, const std::string& b){
    auto its = std::mismatch(a.begin(), std::next(a.begin(),std::min(a.size(),b.size())),b.begin());
    if (its.first == a.end() && its.second == b.end()) {
        std::cout << "the strings are equal\n";
    } else if (its.first != a.end() && its.second != b.end()){
        std::cout << "the strings differ at " << *(its.first) << " and " << *(its.second) << "\n";
    } else if (its.first == a.end()) {
        std::cout << "the second string starts with the first\n";
    } else if (its.second == b.end()) {
        std::cout << "the first string start with the second\n";
    }
}
int main() {
    mism("foo1abc","foo2abc");
    mism("foo","foo");
    mism("foo123","foo");
    mism("foo","foo123");

}

C++ 相当于 Java StringUtils.indexOfDifference

C++ equivalent of Java StringUtils.indexOfDifference

c++

string-comparison