C#字符计分程序末尾多余加号问题解决咨询

我写了一个字符计分程序，输入单词（比如hello）时，程序输出是4 + 1 + 3 + 3 + 1 += 12，但预期应该是4 + 1 + 3 + 3 + 1 = 12——末尾多了个多余的加号。现有C#代码如下：

Console.Write("Give a word: ");
string word = Console.ReadLine();
string smallword = word.ToLower();


int sum = 0;
foreach (char letter in smallword)
{
    int index = Array.IndexOf(alphabet, letter);
    int score = scores[index];
    sum = sum + score;
    string addingEverythingTogether = $" {score} +";
    Console.Write(addingEverythingTogether);
}
Console.Write($"= {sum}");

解决方案 #

方法1：收集分数后用string.Join拼接（推荐）

这种方式避免在循环里处理加号的逻辑，代码更简洁易读，是最省心的实现方式：

Console.Write("Give a word: ");
string word = Console.ReadLine();
string smallword = word.ToLower();

int sum = 0;
List<string> scoreTexts = new List<string>();

foreach (char letter in smallword)
{
    int index = Array.IndexOf(alphabet, letter);
    int score = scores[index];
    sum += score;
    scoreTexts.Add(score.ToString());
}

// 用" + "连接所有分数，再拼接等号和总和
Console.WriteLine($" {string.Join(" + ", scoreTexts)} = {sum}");

方法2：循环中判断是否为最后一个字符

通过跟踪当前字符的索引，判断是否是最后一个，最后一个字符只输出分数不输出加号：

Console.Write("Give a word: ");
string word = Console.ReadLine();
string smallword = word.ToLower();

int sum = 0;
int totalLetters = smallword.Length;
int currentPos = 0;

foreach (char letter in smallword)
{
    currentPos++;
    int index = Array.IndexOf(alphabet, letter);
    int score = scores[index];
    sum += score;
    
    if (currentPos == totalLetters)
    {
        Console.Write($" {score}");
    }
    else
    {
        Console.Write($" {score} +");
    }
}
Console.Write($" = {sum}");

方法3：单独处理第一个字符，后续字符先加再输出

先输出第一个分数，之后的每个字符先输出加号再输出分数，自然不会出现末尾多余加号：

Console.Write("Give a word: ");
string word = Console.ReadLine();
string smallword = word.ToLower();

// 处理空输入的情况
if (string.IsNullOrWhiteSpace(smallword))
{
    Console.WriteLine("= 0");
    return;
}

int sum = 0;
// 输出第一个分数
char firstChar = smallword[0];
int firstIndex = Array.IndexOf(alphabet, firstChar);
int firstScore = scores[firstIndex];
sum += firstScore;
Console.Write($" {firstScore}");

// 处理剩余字符
for (int i = 1; i < smallword.Length; i++)
{
    char letter = smallword[i];
    int index = Array.IndexOf(alphabet, letter);
    int score = scores[index];
    sum += score;
    Console.Write($" + {score}");
}
Console.Write($" = {sum}");

内容的提问来源于stack exchange，提问作者laboonx