C# Coding Questions

 Q 1) Write a program in C# Sharp to reverse a string?

Answer: 

internal static void ReverseString(string str) 
{ 
   
  char[] charArray = str.ToCharArray(); 
  for (int i = 0, j = str.Length - 1; i < j; i++, j--) 
  { 
      charArray[i] = str[j]; 
      charArray[j] = str[i]; 
  } 
  string reversedstring = new string(charArray); 
  Console.WriteLine(reversedstring); 
}

Q 2) Write a program in C# Sharp to reverse the order of the given words?

Answer: 

internal static void ReverseWordOrder(string str) 
{ 
  int i; 
  StringBuilder reverseSentence = new StringBuilder(); 
   int Start = str.Length - 1; 
  int End = str.Length - 1; 
   while (Start > 0) 
  { 
      if (str[Start] == ' ') 
      { 
          i = Start + 1; 
          while (i <= End) 
          { 
              reverseSentence.Append(str[i]); 
              i++; 
          } 
          reverseSentence.Append(' '); 
          End = Start - 1; 
      } 
      Start--; 
  } 
   for (i = 0; i <= End; i++) 
  { 
      reverseSentence.Append(str[i]); 
  } 
  Console.WriteLine(reverseSentence.ToString()); 
}

Q 3) Write a program in C# Sharp to find if a given string is palindrome or not?

Answer: 

internal static void chkPalindrome(string str) 
{ 
   bool flag = false; 
   for (int i = 0, j = str.Length - 1; i < str.Length / 2; i++, j--) 
   { 
       if (str[i] != str[j]) 
       { 
           flag = false; 
           break; 
       } 
       else 
           flag = true; 
   } 
   if (flag) 
   { 
       Console.WriteLine("Palindrome"); 
   } 
   else 
       Console.WriteLine("Not Palindrome");
}

Output: Input: Key Output: Not Palindrome Input: step on no pets Output: Palindrome

Q 4) Write a C# program to find the substring from a given string.

Answer: 

internal static void findallsubstring(string str) 
{ 
   for (int i = 0; i < str.Length; ++i) 
   { 
       StringBuilder subString = new StringBuilder(str.Length - i); 
       for (int j = i; j < str.Length; ++j) 
       { 
           subString.Append(str[j]); 
           Console.Write(subString + " "); 
       } 
   } 
} 

Q 5) Write a C# program to find if a positive integer is prime or not?

Answer: 

static void Main(string[] args) 
{ 
    if (FindPrime(47)) 
    { 
        Console.WriteLine("Prime"); 
    } 
    else 
    { 
        Console.WriteLine("Not Prime"); 
    } 
    Console.ReadLine(); 
}