替换空格

 1 class Solution {
 2 public:
 3     //length为str指向区域可以容纳的字符上限
 4     void replaceSpace(char *str,int length) {
 5         if(str==NULL||length<=0)
 6             return;
 7         int originalLength=0;//字符数目
 8         int numberOfBlank=0;//字符间的空格数目
 9         int i=0;
10         while(str[i]!=‘\0‘)
11         {
12             ++originalLength;
13             if(str[i]==‘ ‘)
14                 ++numberOfBlank;
15             ++i;
16         }   
17         int newLength=originalLength+numberOfBlank*2;
18         if(newLength>length)
19             return;
20         int indexOfOriginal=originalLength;
21         int indexOfNew=newLength;
22         while(indexOfOriginal>=0&&indexOfOriginal<indexOfNew)
23         {
24             if(str[indexOfOriginal]==‘ ‘)
25             {
26                 str[indexOfNew--]=‘0‘;
27                 str[indexOfNew--]=‘2‘;
28                 str[indexOfNew--]=‘%‘;
29             }
30             else
31             {
32                str[indexOfNew--]=str[indexOfOriginal]; 
33             }      
34             --indexOfOriginal;
35         }
36     }
37 };

 1 class Solution {
 2 public:
 3     //length为str的长度
 4     string replaceSpace(string str,int length) {
 5         int i=0; 
 6         while(i < str.size()) 
 7         { 
 8             if(str[i]== ‘ ‘){                  
 9                 str.replace(i,1,"%20"); 
10                 i+=3;  
11             } 
12             else 
13                 i++; 
14         } 
15         return str; 
16     }
17 };