C 언어는 문자열의 맨 끝 공백을 제거합니다

/*
C           ，trim()    
https://blog.csdn.net/u013022032/article/details/50521465
*/ 
#include  
#include  
#include <string.h> 
#include  

//           \t 
 \r  
/*
         ：
' '     (0x20)    space (SPC)    
'\t'    (0x09)    horizontal tab (TAB)          
'
'    (0x0a)    newline (LF)    
'\v'    (0x0b)    vertical tab (VT)      
'\f'    (0x0c)    feed (FF)    
'\r'    (0x0d)    carriage return (CR)    
//windows \r
 linux 
 mac \r
*/ 
char *rtrim(char *str) 
{ 
    if (str == NULL || *str == '\0') 
    { 
        return str; 
    } 
    int len = strlen(str); 
    char *p = str + len - 1; 
    while (p >= str && isspace(*p)) 
    { 
        *p = '\0'; --p; 
    } 
    return str; 
} 


//       
char *ltrim(char *str) 
{ 
    if (str == NULL || *str == '\0') 
    { 
        return str; 
    } 
    int len = 0; 
    char *p = str;
    while (*p != '\0' && isspace(*p)) 
    { 
        ++p; ++len; 
    } 
    memmove(str, p, strlen(str) - len + 1); 
    return str; 
} 


//       

char *trim(char *str) 
{ 
    str = rtrim(str); 
    str = ltrim(str); 
    return str; 
} 

void demo() 
{ 
    char str[] = "   ab  c \r 
 \t";
    printf("before trim:%s
", str); 
    char *p = trim(str); 
    printf("after trim:%s
", p); 
} 

int main(int argc, char **argv) 
{ 
    demo(); 
    return 0; 
}