实现strcat功能

Posted 2020-06-17

实现两个字符串相连


 1 #include<stdio.h>
 2 #include<string.h>
 3 
 4 //把源字符串连接到目的字符串中
 5 char *strcat1(char *dest,const char *src)
 6 {
 7     int i=0;
 8     int n=strlen(dest);
 9 
10     if((dest != NULL) && (src != NULL))        //源指针和目的指针不能为NULL
11     {
12         for(i=0;src[i] != ‘\0‘;i++)
13         {
14             dest[n+i] = src[i];
15         }
16         dest[n+i] = ‘\0‘;
17     }
18 
19     return dest;
20 }
21 
22 //从源字符串中，连几个字符到目的字符串中
23 char *strcat2(char *dest,const char *src,int num)
24 {
25     int i=0;
26     int n= strlen(dest);
27 
28     if((dest != NULL) && (src != NULL))        //源指针和目的指针不能为NULL
29     {
30         for(i=0;i<num && src[i] != ‘\0‘;i++)
31         {
32             dest[n+i] = src[i];
33         }
34         dest[n+i] = ‘\0‘;
35     }
36 
37     return dest;
38 }
39 
40 
41 int main()
42 {
43     char a[20]="hello ";
44     char *p="world!123";
45     //测试strcat1函数
46     strcat1(a,p);
47     printf("After strcat1 function,a=%s\n",a);
48 
49     //测试strcat2函数
50     char b[20]="beautiful ";
51     strcat2(b,p,6);
52     printf("After strcat2 function,b=%s\n",b);
53 
54     return 0;
55 }