Question

为什么我从这两个版本的代码中得到不同的结果？换句话说，为什么theme没有在第二个代码块中生效？

#include "stdafx.h"
#include<iostream>
#include<conio.h>

using namespace std;

class rez {
    float r;
public:
    void set(int n);
    float val() { return r; }
};

void rez :: set(int n) {           //n is the number of resistances
    int i;
    for (i = 1; i <= n; i++) {

        cout << "R" << i << "=";  
        cin >> r;
    }

}

float serie(rez r1,int n)
{
    float s=0;
    int i;
    for (i = 1; i <= n; i++)
    {
        s = s+ r1.val();
    }
    return s;
}

float para(rez r1, int n)
{
    float s = 0;
    int i;
    for (i = 1; i <= n; i++)
    {
        s = s + (1/r1.val());
    }
    return 1/s;
}


int main()
{
    char c, k = 'y';    // 'c' selects series or para
    rez r1;               
    int n;
    cout << "number of resis:";
    cin >> n;
    cout << endl;
    while (k != 'q')
    {
            r1.set(n);
            float i, u;
            cout << "\n Vdc= ";
            cin >> u;
            cout << endl;

        cout << "series or para(s/p)?"<<endl;
        cin >> c;
        switch (c)
        {
        case('s'):cout <<"\n equiv resistance = "<< serie(r1,n)<<endl;
            i = u / serie(r1, n);
            cout << "curr i = " << i << " amp";
            break;
        case('p'):cout << "\n equiv res = " << para(r1, n)<<endl;
            i = u / para(r1, n);
            cout << "cur i = " << i << " amp";
            break;
        }



        cout <<endl<< "\n another set?(y/q)?"<<endl;
        cin >> k;

    }
    return 0;
}

输出：

word = word[i..-1]

和

def translate(input)
    output_array = input.split(" ").each do |word|

      i=0
      while !['a', 'e', 'i', 'o', 'u'].include?(word[i])
        i += 1
      end

      unless i == 0 
        word << word[0..i-1]
        word[0..i-1] = ''
      end

      word << "ay"

  end
  return output_array.join(" ")
end

puts translate('apple')
puts translate('banana')
puts translate('trash')
puts translate('eat pie')

打印出来：

appleay
ananabay
ashtray
eatay iepay

Answer 1

output_array = input.split(" ").each do |word|

  i=0
  while !['a', 'e', 'i', 'o', 'u'].include?(word[i])
    i += 1
  end

  unless i == 0 
    word << word[0..i-1] # Good
    word = word[i..-1] # Bad
  end

  word << "ay"

end

该行

word << word[0..i-1]

更改字符串，而

word = word[i..-1]

创建一个新字符串并将新字符串分配给word。更改新字符串不会影响数组中的旧字符串，因此数组中的单词保持在

之后的字样

word << word[0..i-1]

进行每次修改（就像你在解决方案1中所做的那样），或者使用更像Ruby的Array#map。

这是偏离主题的，但您的while循环可以替换为

i = word.index(/[aeiou]/)

如果你碰巧知道正则表达式。

如何在Ruby中进行字符串切片

1 个答案: