在vector<float> C++中查找特定的第一个和最后一个索引

 int main() {

     std::vector<float> numbers = {1.2, 3.4, 5.6, 7.8, 9.0, 3.4, 5.6};

     float target = 3.4;

     auto it = std::find(numbers.begin(), numbers.end(), target);

     if (it != numbers.end()) {

         int index = std::distance(numbers.begin(), it);

         std::cout << "First index of " << target << ": " << index << std::endl;

     } else {

         std::cout << "Target value not found." << std::endl;

     }

     return 0;

 }

 ```

 int main() {

     std::vector<float> numbers = {1.2, 3.4, 5.6, 7.8, 9.0, 3.4, 5.6};

     float target = 3.4;

     auto it = std::find(std::make_reverse_iterator(numbers.end()), std::make_reverse_iterator(numbers.begin()), target);

     if (it != std::make_reverse_iterator(numbers.begin())) {

         int index = std::distance(numbers.begin(), --it.base());

         std::cout << "Last index of " << target << ": " << index << std::endl;

     } else {

         std::cout << "Target value not found." << std::endl;

     }

     return 0;

 }

 ```

 int main() {

     std::vector<float> numbers = {1.2, 3.4, 5.6, 7.8, 9.0, 3.4, 5.6};

     float target = 3.4;

     std::vector<int> indices;

     for (int i = 0; i < numbers.size(); i++) {

         if (numbers[i] == target) {

             indices.push_back(i);

         }

     }

     if (!indices.empty()) {

         std::cout << "Indices of " << target << ": ";

         for (int index : indices) {

             std::cout << index << " ";

         }

         std::cout << std::endl;

     } else {

         std::cout << "Target value not found." << std::endl;

     }

     return 0;

 }

 ```