c語言實現去除字符串首位空格，字符串首位空格

c語言實現去除字符串首位空格，字符串首位空格

字符串內存圖如下:

引入頭文件:

 1 #include<stdlib.h>
 2 #include<stdio.h>
 3 #include<string.h>

 函數原型:

1 void trim(char *strIn /*in*/, char *strOut /*in*/);

實現方法一:

void trim(char *strIn, char *strOut){

    int i, j ;

    i = 0;

    j = strlen(strIn) - 1;

    while(strIn[i] == ' ')
        ++i;

    while(strIn[j] == ' ')
        --j;
    strncpy(strOut, strIn + i , j - i + 1);
    strOut[j - i + 1] = '\0';
}

實現方法二:

 1 void trim(char *strIn, char *strOut){
 2 
 3     char *start, *end, *temp;//定義去除空格後字符串的頭尾指針和遍歷指針
 4     
 5     temp = strIn;
 6 
 7     while (*temp == ' '){
 8         ++temp;
 9     }
10 
11     start = temp; //求得頭指針
12 
13     temp = strIn + strlen(strIn) - 1; //得到原字符串最後一個字符的指針(不是'\0')
14 
15     printf("%c\n", *temp);
16 
17     while (*temp == ' '){
18         --temp;
19     }
20 
21     end = temp; //求得尾指針
22     
23 
24     for(strIn = start; strIn <= end; ){
25         *strOut++ = *strIn++;
26     }
27 
28     *strOut = '\0';
29 }

測試:

 1 void main(){
 2     char *strIn = "   ak kl  p  ";
 3 
 4     char strOut[100];
 5 
 6     trim(strIn, strOut);
 7 
 8     printf("*%s*\n",strOut);
 9 
10     system("pause");
11 }