Types of data in C #

In C + +, a value of type bool can be converted to a value of type int, and false is equivalent to a value of 0, and true is equivalent to a value other than 0. However, in the C # language, there is no reciprocal conversion between the bool type and other types. For example, the following if statement is illegal in C # and is legal in C + +:

int x = 123;
if (x)　 // 注意：在C#中此语句是错误的
{
　　printf("x is 非零值.");
}

To test a variable of type int, you must explicitly compare the variable with a value, such as 0, as follows:

int x = 123;
if (x != 0)　 // C#的判断方式
{
　　Console.Write("The value of x is nonzero.");
}

Function Description: Enter a character from the keyboard, and then the program checks whether the entered character is a letter. If the character entered is a letter, the program check is uppercase or lowercase. These checks are performed using Isletter and Islower (both of which return the bool type).

using System;
public class BoolTest1
{
　　static void Main()
　　{
　　　　Console.Write("请输入一个字母: ");
　　　　char c = (char)Console.Read();
　　　　if (Char.IsLower(c))
　　　　{
　　　　　　　　Console.WriteLine("这个字符是小写字母.");
　　　　}
　　　　else
　　　　{
　　　　　　　　Console.WriteLine("这个字符是大写字母.");
　　　　}
　　}
}

There are predefined implicit conversions from byte to short, ushort, int, uint, long, ulong, float, double, or decimal.

Attention

You cannot implicitly convert a non-literal numeric type of a larger storage range to byte.

such as: byte z = x + y;

The above assignment statement will result in a compilation error because the arithmetic expression on the right side of the assignment operator evaluates to the int type by default.

To resolve this issue, use the cast:

byte z = (byte) (x + y);