函数讲解部分参考http://net.pku.edu.cn/~yhf/linux_c/

Linux实例程序代码如下:

#include <stdio.h>

#include <ctype.h>


void isalnum_fun(char *str);

void isalpha_fun(char *str);

void isdigit_fun(char *str);

void isgraphis_fun(char *str);

void islower_fun(char *str);

void isprint_fun(char *str);

void isspace_fun(char *str);

void ispunct_fun(char *str);

void isupper_fun(char *str);

void isxdigit_fun(char *str);

int main()

{
	
	int Index;
	
	char str[40];

	
	printf("1.isalnum_fun()\n");
	
	printf("2.isalpha_fun()\n");
	
	printf("3.isdigit_fun()\n");
	
	printf("4.isgraphis_fun()\n");
	
	printf("5.islower_fun()\n");
	
	printf("6.isprint_fun()\n");
	
	printf("7.isspace_fun()\n");
	
	printf("8.ispunct_fun()\n");
	
	printf("9.isupper_fun()\n");
	
	printf("10.isxdigit_fun()\n");
	
	
	printf("Please input the String:\n");
	
	gets(str);

	
	while(1)
	
	{
		
		printf("Please input the operator you want done (0-exit):\n");
		
		scanf("%d",&Index);
		
		
		if(Index==0)
		
		{
			
			printf("Bye Bye!\n");
			
			break;
		
		}
		
		else
		
		{
			
		       switch(Index)
			
		      {
				
			     case 1:isalnum_fun(str);
					   
			        break;
				
			     case 2:isalpha_fun(str);
					   
			        break;
				
			     case 3:isdigit_fun(str);
					  
			        break;
				
			     case 4:isgraphis_fun(str);
					  
			        break;
				
			     case 5:islower_fun(str);

			        break;
				
			     case 6:isprint_fun(str);
					   
			        break;
				
			     case 7:isspace_fun(str);
					  
			        break;
				
			     case 8:ispunct_fun(str);
					   
			        break;
				
			     case 9:isupper_fun(str);
					   
			        break;
				
			     case 10:isxdigit_fun(str);
					   
			        break;
			    
			     default:
						
				break;
			
			}
		
		}
	
	  }
	
  return 0;

}



void isalnum_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++);
	
	{
		
		if(isalnum(str[i]))
			
			printf("%c is an alphanumberic character\n",str[i]);
	
	}

}



void isalpha_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(isalpha(str[i]))
			
			printf("%c is an alphanumberic character\n",str[i]);
	
	}

}



void isdigit_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(isdigit(str[i]))
			
		printf("%c is an digit character\n",str[i]);
	
	}

}



void isgraphis_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(isgraph(str[i]))
			
			printf("str[%d] is printable character:%c\n",i,str[i]);
	
	}

}



void islower_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(islower(str[i]))
			
			printf("%c is an low_case character\n",str[i]);
	
	}

}



void isprint_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(isprint(str[i]))
		
			printf("str[%d] is printable character:%c\n",i,str[i]);
	
	}
	

}



void isspace_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{

			if(isspace(str[i]))
	
				printf("str[%d] is a white_space character:%d\n",i,str[i]);
	
	}	

}



void ispunct_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(ispunct(str[i]))
			
			printf("%c\n",str[i]);
	
	}

}



void isupper_fun(char *str)

{
	
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(isupper(str[i]))
			
			printf("%c is an upper_case character\n",str[i]);
	
	}

}



void isxdigit_fun(char *str)

{
	int i;
	
	for(i=0;str[i]!=0;i++)
	
	{
		
		if(isxdigit(str[i]))
			
			printf("%c is an hex digits\n",str[i]);

	}

}

转载请注明:小刘

Linux常用C函数---字符测试篇