C # Certification Exam questions.

1.1, enter a positive integer n, if it is an even number to find all the even number within N, and an odd number of N to find all the odd and.

static void Main (string[] args)
{
int result=0;
Console.WriteLine ("Please enter a positive integer:");
int n = Convert.ToInt32 (Console.ReadLine ());
if (n%2==0)
{
for (int i = 0; I <= N; i++)
if (i% 2 = = 0)
result + = i;
}
Else
{
for (int i = 0; I <= N; i++)
if (i% 2! = 0)
result + = i;
}
Console.WriteLine ("Result: {0}", result);
Console.ReadLine ();

}

1.2. Enter a positive integer to output all the approximate numbers.

static void Main (string[] args)
{
Console.WriteLine ("Please enter a positive integer:");
int n = Convert.ToInt32 (Console.ReadLine ());
if (n% 2 = = 0)
{
for (int i = 2; I <= n/2; i++)
{
if (n% i = = 0)
{
Console.WriteLine (i);
}
}
}
Else
{
for (int i=3;i<= (n-1)/2;i++)
{
if (n%i==0)
{
Console.WriteLine (i);
}
}
}
Console.ReadLine ();
}

1.3-1.4, enter two positive integers, seek greatest common divisor, least common multiple.

static void Main (string[] args)
{
int result=1;
Console.WriteLine ("Please enter the first positive integer:");
int a = Convert.ToInt32 (Console.ReadLine ());
int x = A;
Console.WriteLine ("Please enter a second positive integer:");
int b = Convert.ToInt32 (Console.ReadLine ());
int y = b;
if (a > B)
{
int t = A;
A = b;
b = t;

}
while (true)
{

if (b% A = = 0)
{
result = A;
Break
}
Else
{
int ys = b% A;
b = A;
A = ys;
}

}
int RESULT1 = x * y/result;
Console.WriteLine ("Greatest common divisor for: {0}", result);
Console.WriteLine ("Least common multiple: {0}", RESULT1);
Console.ReadLine ();

}

1.5, judge the prime number.

static void Main (string[] args)
{
BOOL Prime=true;
Console.WriteLine ("Please enter a positive integer:");
int n = Convert.ToInt32 (Console.ReadLine ());
for (int i=2;i<=n/2;i++)
{
if (n% i = = 0)
Prime = false;
Break
}
if (prime)
Console.WriteLine ("{0} is a prime number", N);
Else
Console.WriteLine ("{0} is not a prime number", N);
}

1.6.

1.9. Find the most ASCII characters in a string

static void Main (string[] args)

{

Console.WriteLine ("Please enter a string:");

String s_text = Convert.ToString (Console.ReadLine ());

Char ch;

ch = s_text[0];

for (int i = 0; i < S_text. Length; i++)

{

if (Ch < s_text[i])

ch = s_text[i];

}

Console.WriteLine ("ASCII maximum character is {0}", ch);

Console.ReadLine ();

}

1.10. find the smallest ASCII character in a string

static void Main (string[] args)

{

Console.WriteLine ("Please enter a string:");

String s_text = Convert.ToString (Console.ReadLine ());

Char ch;

ch = s_text[0];

for (int i = 0; i < S_text. Length; i++)

{

if (Ch > s_text[i])

ch = s_text[i];

}

Console.WriteLine ("ASCII minimum character is {0}", ch);

Console.ReadLine ();

}

1.11. Enter the original string and the key string, and output the result of encrypting the string.

static void Main (string[] args)
{
String S_text, S_key;
string s_result = null;
Char ch;
Console.WriteLine ("Please enter the original string:");
S_text =convert.tostring (Console.ReadLine ());
Console.WriteLine ("Please enter the key string:");
S_key = Convert.ToString (Console.ReadLine ());
if (S_text. Length! = S_key. Length)
{
Console.WriteLine ("The key string must be equal to the original string length!") ");
}
Else
{
for (int i=0;i<s_text. length;i++)
{
ch = s_text[i];
S_result + = ch ^ s_key[i];

}
Console.Write ("The string after encryption is:");

}
Console.WriteLine (S_result);
Console.ReadLine ();
}

int x = Convert.ToInt32 (id[18]);

C # Certification Exam questions.