12.字符串全部替换指定文本

Posted 2020-10-22 喵小喵~

运行结果:

 

 完整代码:

  1 #define _CRT_SECURE_NO_WARNINGS
  2 #include <stdlib.h>
  3 #include <stdio.h> 
  4 #include <string.h>
  5 
  6 void replaceAll(char *ppstr, char *from, char *to)
  7 {
  8     //备份地址
  9     //首地址,用于被赋值
 10     char *start1 = ppstr;
 11     //游标,用于给start1赋值
 12     char *start2 = ppstr;
 13     //求出要被转换的字符串和要被转成的字符串长度,分三种情况讨论
 14     int length1 = strlen(from);
 15     int length2 = strlen(to);
 16     //如果要替换的字符串长度和原来的相等
 17     if (length1 == length2)
 18     {
 19         while ((*start1 = *start2) != \'\\0\')
 20         {
 21             //假定找到子串
 22             int flag = 1;
 23             //判断是否找到子串
 24             for (int i = 0; i < strlen(from); i++)
 25             {
 26                 if (start2[i] != from[i] || start2[i] == \'\\0\')
 27                 {
 28                     flag = 0;
 29                     break;
 30                 }
 31             }
 32 
 33             //如果没找到子串,被赋值的地址自增,游标自增
 34             if (flag == 0)
 35             {
 36                 start1++;
 37                 start2++;
 38             }
 39             else//如果找到了,则进行替换
 40             {
 41                 //start2 += length1;//删除
 42                 //赋值
 43                 for (int i = 0; i < length1; i++)
 44                 {
 45                     start1[i] = to[i];
 46                 }
 47                 //前进
 48                 start1 += length1;
 49                 start2 += length1;
 50             }
 51         }
 52     }
 53     //如果要替换的字符串长度大于原来的长度
 54     else if(length1 < length2)
 55     {
 56         while ((*start1 = *start2) != \'\\0\')
 57         {
 58             //假定相等
 59             int flag = 1;
 60             for (int i = 0; i < strlen(from); i++)
 61             {
 62                 if (start2[i] != from[i] || start2[i] == \'\\0\')
 63                 {
 64                     flag = 0;
 65                     break;
 66                 }
 67             }
 68 
 69             if (flag == 0)
 70             {
 71                 start1++;
 72                 start2++;
 73             }
 74             else
 75             {
 76                 //start2 += length1;//删除
 77                 //求出差距
 78                 int chaju = length2 - length1;
 79                 //整体向后移动,留出空位
 80                 for (char *ptemp = ppstr + strlen(ppstr); ptemp >= start1 + length1; ptemp--)
 81                 {
 82                     *(ptemp + chaju) = *ptemp;
 83                 }
 84                 //把空位填充数据
 85                 for (int i = 0; i < length2; i++)
 86                 {
 87                     start1[i] = to[i];
 88                 }
 89                 //游标和地址移动
 90                 start1 += length2;
 91                 start2 += length2;
 92             }
 93         }
 94     }
 95     //如果要替换的字符串长度小于原来的长度
 96     else if (length1 > length2)
 97     {
 98         while ((*start1 = *start2) != \'\\0\')
 99         {
100             //假定相等
101             int flag = 1;
102             for (int i = 0; i < strlen(from); i++)
103             {
104                 if (start2[i] != from[i] || start2[i] == \'\\0\')
105                 {
106                     flag = 0;
107                     break;
108                 }
109             }
110 
111             if (flag == 0)
112             {
113                 start1++;
114                 start2++;
115             }
116             else
117             {
118                 //start2 += length1;//删除
119                 //赋值
120                 int chaju = length1 - length2;
121                 //整体向前移动,压缩数据
122                 for (char *ptemp = start1 + length2; *ptemp != \'\\0\'; ptemp++)
123                 {
124                     *ptemp = *(ptemp + chaju);
125                     if (*(ptemp + chaju) == \'\\0\')
126                     {
127                         break;
128                     }
129                 }
130 
131                 //填充
132                 for (int i = 0; i < length2; i++)
133                 {
134                     start1[i] = to[i];
135                 }
136 
137                 //游标和地址移动
138                 start1 += chaju;
139                 start2 += chaju;
140             }
141         }
142     }
143 
144 
145 }
146 
147 void main()
148 {
149     char str[100] = "我爱中国 我爱南京 我爱上海 我爱家庭";
150     char from[10] = "我";
151     char to[10] = "我和你";
152     printf("原数据:%s\\n", str);
153     printf("要被替换的数据:%s\\n", from);
154     printf("替换成:%s\\n", to);
155     replaceAll(str, from, to);
156     printf("替换后的数据:%s\\n", str);
157     getchar();
158 }