在C#中,if语句用于指示将根据给定布尔表达式的值执行哪个语句。如果布尔表达式的值为true,则if语句将执行给定的then语句,否则它将控制权返回给if语句之后的下一个语句。
- 在C#中,您可以根据需要将if语句与then语句或else语句一起使用。
- 然后,语句包含一个或多个语句,这些语句用花括号({})括起来。对于单个语句,花括号可以是可选的,如果大括号{}不与if语句一起使用,则仅将其旁边的语句视为与if语句相关联。
- then语句可以是任何类型/类型,例如可以包含另一个if-else语句。
句法:
if(condition)
{
then statement;
}
流程图:
让我们在给定示例的帮助下讨论if语句:
范例1:
C#
// C# program to demonstrate
// if statement
using System;
class GFG{
static public void Main()
{
// Declaring and initializing variables
string x = "GeeksforGeeks";
string y = "GeeksforGeeks";
// If statement
if (x == y)
{
Console.WriteLine("Both strings are equal..!!");
}
// If statement
if (x != y)
{
Console.WriteLine("Both strings are not equal..!!");
}
}
}
C#
// C# program to demonstrate nested
// if statement
using System;
class GFG{
static public void Main()
{
// Declaring and initializing variables
string emp_name = "Rohit";
int salary = 10000;
// If statement
// Here if condition checks
// the employee name is equal to rohit
if (emp_name == "Rohit")
{
// Nested if statement
// Here if the salary of Rohit
// is greater than 50000 then
// he is eligible to pay tax
// Otherwise not eligible
if (salary > 50000)
{
Console.WriteLine("Eligible to pay tax");
}
else
{
Console.WriteLine("Not Eligible");
}
}
}
}
C#
// C# program to illustrate if statement
// Using AND, OR, NOT operators
using System;
class GFG{
static public void Main()
{
// Declaring and initializing variables
int x1 = 15;
int x2 = 18;
int x3 = 20;
// If statement
// Using AND operator
if (x1 > 20 && x2 > 20)
{
Console.WriteLine("Enter group A");
}
// If statement
// Using OR operator
if (x1 < 30 || x3 == 20)
{
Console.WriteLine("Enter group B");
}
// If statement
// Using NOT operator
if (!(x1 > 20 && x2 > 20))
{
Console.WriteLine("Enter group C");
}
}
}
输出:
Both strings are equal..!!
说明:在上面的示例中,我们有两个字符串,即x和y。现在,在第一,if语句,我们字符串x比较字符串y和比较的结果是真。因此,然后执行then块并输出“两个字符串都相等.. !! ”。现在在第二个if语句中,我们检查两个字符串不相等,但是字符串相等,因此,此if语句的then块将不执行。
范例2:
C#
// C# program to demonstrate nested
// if statement
using System;
class GFG{
static public void Main()
{
// Declaring and initializing variables
string emp_name = "Rohit";
int salary = 10000;
// If statement
// Here if condition checks
// the employee name is equal to rohit
if (emp_name == "Rohit")
{
// Nested if statement
// Here if the salary of Rohit
// is greater than 50000 then
// he is eligible to pay tax
// Otherwise not eligible
if (salary > 50000)
{
Console.WriteLine("Eligible to pay tax");
}
else
{
Console.WriteLine("Not Eligible");
}
}
}
}
输出:
Not Eligible
范例3:
C#
// C# program to illustrate if statement
// Using AND, OR, NOT operators
using System;
class GFG{
static public void Main()
{
// Declaring and initializing variables
int x1 = 15;
int x2 = 18;
int x3 = 20;
// If statement
// Using AND operator
if (x1 > 20 && x2 > 20)
{
Console.WriteLine("Enter group A");
}
// If statement
// Using OR operator
if (x1 < 30 || x3 == 20)
{
Console.WriteLine("Enter group B");
}
// If statement
// Using NOT operator
if (!(x1 > 20 && x2 > 20))
{
Console.WriteLine("Enter group C");
}
}
}
输出:
Enter group B
Enter group C