#include <iostream>
#include <string>
using namespace std;
string multiply(int num) {
int multiple = 0;
int multiplied = 0;
string num2;
if(num<=10){
while (num!=0){
for(multiple=0;multiple<10;multiple++){
multiplied = num*multiple;
std::string num1 = to_string(multiplied);
std:string space = " ";
num2 += num1 + space;
}
}
return num2;
cout << num2 << endl;
}
}
int main(){
int num = 5;
multiply(num);
}
这是我用C ++编写的代码,可以编译,但不能执行任何操作,我将VSCODE与Windows wsl和atom编辑器配合使用,我试图学习C ++中的规则和操作。谁能给我点子。我还测试了许多cout语句,却不知道它在做什么,
谢谢
答案 0 :(得分:1)
a
返回值,然后才能打印。
此外,条件为 private void Button2_Click(object sender, EventArgs e)
{
string[] lines = File.ReadAllLines("persons.txt");
Person[] persons = new Person[lines.Length];
int index = 0;
foreach (string s in lines)
{
string[] arr = s.Split(',');
persons[index] = new Person(arr[0], arr[1], arr[2]);
}
DataTable dt = new DataTable();
using (SqlConnection cn = new SqlConnection(Properties.Settings.Default.CoffeeConnection))
using (SqlCommand cmd = new SqlCommand("Select * From Person Where FirstName = @FName And MiddleName = @MName And LastName = @LName;", cn))
{
cmd.Parameters.Add("@FName", SqlDbType.VarChar, 100);
cmd.Parameters.Add("@MName", SqlDbType.VarChar, 100);
cmd.Parameters.Add("LName", SqlDbType.VarChar, 100);
cn.Open();
foreach (Person p in persons)
{
cmd.Parameters["@FName"].Value = p.firstName;
cmd.Parameters["@MName"].Value = p.middleName;
cmd.Parameters["@LName"].Value = p.lastName;
dt.Load(cmd.ExecuteReader());
}
}
dataGridView1.DataSource = dt;
}
,但是var dropdownButton = DropdownButtonHideUnderline(
child: DropdownButton(
value: dropdownValue,
onChanged: (String newValue) {
setState(() {
dropdownValue = newValue;
});
},
items: <String>['99451', '99450', '99455', '99470 '].map<DropdownMenuItem<String>>
((String value) {
return DropdownMenuItem<String>(
value: value,
child: Text(value),
);
}).toList(),
)
);
在这里从未更改,因此进入无限循环。
下面的代码将提供输出:
return num2;
cout << num2 << endl;
输出为:while (num!=0)