Question

我的代码中有错误，这是我的代码：

#include "stdafx.h"
#include <vector>
#include <iostream>
using namespace std;

int main(){
    vector<int> numbers(0);
    cout << "please enter you numbers :::\n''entering any characters but numbers is the end of entry''";
    char ch;
    int i = 0;
    while (Isnumber(ch)){    //here is the error
        do{
            ch = getchar();
            int newnumber = 0;
            cout << "element(" << i << ") = ";
            cin >> newnumber;
            numbers.push_back(newnumber);
        } while (ch>0 || ch < 9);
    }   
    getchar();
}

两个错误，它说标识符未知，和它说变量char是uninitialazed局部变量，

Answer 1

将此 while (Isnumber(ch)){ 更改为do-while循环。

do{
  .....
}while (Isnumber(ch))

错误是因为声明了 ch并且在初始化之前使用了它。

还包括#include <stdio.h>; for getchar();

Answer 2

最好在一个循环中完成：

do {
    ch = getchar();
    int newnumber = 0;
    cout << "element(" << i << ") = ";
    cin >> newnumber;
    numbers.push_back(newnumber);
} while (Isnumber(ch)); // should probably be isdigit(ch)

在提出类似问题之前先阅读this（或购买book）。

Answer 3

我用cin函数解决了它，如下所示，

#include "stdafx.h"
#include <vector>
#include <iostream>
using namespace std;

int main(){
    vector<int> numbers(0);
    cout << "please enter you numbers :::\n''entering any characters but numbers is the end of entry''\n";
    //char ch;
    int counter = 0;    
        do{         
            int newnumber = 0;
            cout << "element(" << counter << ") = ";
            counter++;
            cin >> newnumber;
            numbers.push_back(newnumber);
            if (cin.fail()){
                cout << "entered numbers are:\n";
                for (vector<int>::iterator i = numbers.begin(); i != numbers.end(); i++)
                {
                    cout << *i;
                    if (i != numbers.end()-1)cout << " - ";
                }               
            }
        } while (cin.good());
        getchar();
}

我删除了一个while循环。并使用cin.fail和cin.good来避免使用IsNumber。它起作用了。

char未初始化，isnumber方法未识别，

3 个答案: