C 语言检查字符是小写字母还是大写字母的程序

编写一个C语言程序，使用内置函数和ASCII码检查字符是小写字母还是大写字母。

C 语言检查字符是小写字母还是大写字母的程序

此程序允许用户输入任何字符，并使用内置函数 `isupper` 和 `islower` 检查该字符是否为大写字母。

在C语言编程中，<ctype.h>头文件中有称为isupper和islower的内置函数。您可以使用这些函数来检查字符是小写字母还是大写字母。

#include<stdio.h>
#include<ctype.h>

int main()
{
	char Ch;
 
  	printf("\n Please Enter any alphabet  :  ");
  	scanf("%c", &Ch);
 
  	if ( islower(Ch) )
   	{  
    	printf ("\n Entered character is a Lowercase Alphabet");
   	}
    else if ( isupper(Ch) )
   	{  
    	printf ("\n Entered character is an Uppercase Alphabet");
   	}
  	else
   	{
    	printf("\n Entered character is Not an Alphabet");
   	}
	return 0;   
}

 Please Enter any alphabet  :  T

 Entered character is an Uppercase Alphabet

输出 2

 Please Enter any alphabet  :  g

 Entered character is a Lowercase Alphabet

第三个输出

 Please Enter any alphabet  :  9

 Entered character is Not an Alphabet

程序示例2：检查字符是小写字母还是大写字母

在这个程序中，我们不使用 `isupper` 或 `islower` 函数。相反，我们将字母直接放在If 语句中。

#include<stdio.h>

int main()
{
 	char Ch;
 
  	printf("\n Please Enter any alphabet\n");
  	scanf("%c", &Ch);
 
  	if (Ch >= 'a' && Ch <= 'z')
   	{  
    	printf ( "\n Entered character is a Lowercase Alphabet") ;
   	}
   	else if (Ch >= 'A' && Ch <= 'Z')
  	{  
    	printf ( "\n Entered character is an Uppercase Alphabet") ;
   	}
  	else
   	{
    	printf("\n Entered character is Not an Alphabet");
   	} 
	return 0;    
}

 Please Enter any alphabet
k

 Entered character is a Lowercase Alphabet

让我们用一个错误的值来检查

 Please Enter any alphabet
@

 Entered character is Not an Alphabet

程序示例3：检查字符是小写字母还是大写字母

在此程序中，我们使用ASCII表码来检查字符是大写字母还是小写字母。

#include<stdio.h>

int main()
{
 	char Ch;
 
  	printf("\n Please Enter any alphabet\n");
  	scanf("%c", &Ch);
 
  	if (Ch >= 65 && Ch <= 90)
   	{  
    	printf ( "\n Entered character is an Uppercase Alphabet") ;
   	}
   	else if (Ch >= 97 && Ch <= 122)
  	{  
    	printf ( "\n Entered character is a Lowercase Alphabet") ;
   	}
  	else
   	{
    	printf("\n Entered character is Not an Alphabet");
   	} 
	return 0;    
}