front_line.push_back(atof(str.c_str()));是什么意思
时间: 2024-05-25 21:10:13 浏览: 15
这是一段 C++ 代码,其中 `front_line` 是一个 vector 容器,`push_back` 是 vector 容器的一个成员函数,用于在 vector 容器的末尾添加元素。`atof` 是一个 C++ 标准库函数,用于将字符串转换为浮点数。`str.c_str()` 返回一个指向字符串 `str` 的指针,其中 `str` 是一个字符串对象。所以这行代码的含义是将字符串 `str` 转换为浮点数后添加到 `front_line` 的末尾。
相关问题
atof(temp.c_str())
This is a C++ code snippet that converts a C++ string object "temp" to a double data type using the "atof()" function.
The "atof()" function is a standard C++ library function that converts a string containing a numerical value to a double data type. The "c_str()" function is used to convert the string object "temp" to a C-style string (i.e. a null-terminated character array) that is required as an argument to the "atof()" function.
Overall, this code allows the program to convert a string value to a floating-point value, which can be useful for various mathematical and computational operations.
void CTool::load_data_from_db() { myData *db = myData::getMyData(); string sql = "SELECT * FROM car"; int row = 0, col = 0; char ** qres; db->getData_exec(sql.c_str(), row, col, qres); vector<myData> data_list; for (int i = 0; i < row; i++) { myData data; for (int j = 0; j < col; j++) { if (qres[i * col + j] != NULL) { if (j == 0) data.id = atoi(qres[i * col + j]); else if (j == 1) data.name = qres[i * col + j]; else if (j == 2) data.color = qres[i * col + j]; else if (j == 3) data.price = atof(qres[i * col + j]); } } data_list.push_back(data); } for (int i = 0; i < data_list.size(); i++) { CEditBox* edit_box = new CEditBox(x + 10, y + 10 + i * 30, w - 20, 20); edit_box->setText(data_list[i].name + " " + to_string(data_list[i].age)); ctrlArry.push_back(edit_box); } }修改这段代码
void CTool::load_data_from_db() {
myData *db = myData::getMyData();
string sql = "SELECT * FROM car";
int row = 0, col = 0;
char ** qres;
db->getData_exec(sql.c_str(), row, col, qres);
vector<myData> data_list;
for (int i = 0; i < row; i++) {
myData data;
for (int j = 0; j < col; j++) {
if (qres[i * col + j] != NULL) {
if (j == 0)
data.id = atoi(qres[i * col + j]);
else if (j == 1)
data.name = qres[i * col + j];
else if (j == 2)
data.color = qres[i * col + j];
else if (j == 3)
data.price = atof(qres[i * col + j]);
}
}
data_list.push_back(data);
}
for (int i = 0; i < data_list.size(); i++) {
string text = data_list[i].name + " " + to_string(data_list[i].price); // 修改文本框的显示内容
CEditBox* edit_box = new CEditBox(x + 10, y + 10 + i * 30, w - 20, 20);
edit_box->setText(text);
ctrlArry.push_back(edit_box);
}
}
相关推荐
![docx](https://img-home.csdnimg.cn/images/20210720083331.png)
![](https://img-home.csdnimg.cn/images/20210720083646.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)