首先设置字符串 -

string str = "Hello World! Hello!";

现在检查字符串中是否出现单词“Hello”并循环 -

while ((a = str1.IndexOf(pattern, a)) != -1) {
   a += pattern.Length;
   count++;
}

示例

您可以尝试运行以下代码来计算字符串中单词的出现次数。

实时演示

using System;
class Program {
   static void Main() {
      string str = "Hello World! Hello!";
      Console.WriteLine("Occurrence:"+Check.CheckOccurrences(str, "Hello"));
   }
}
public static class Check {
   public static int CheckOccurrences(string str1, string pattern) {
      int count = 0;
      int a = 0;
      while ((a = str1.IndexOf(pattern, a)) != -1) {
         a += pattern.Length;
         count++;
      }
      return count;
   }
}

输出

Occurrence:2