1.模拟实现strcpy
//模拟实现字符串拷贝函数strcpy #include <stdio.h> #include <stdlib.h> char* my_strcpy(char* dest,const char* src) { char* ch = dest; while(*dest++ = *src++)//*(p++)解引用操作符、后置++，结合方向自右向左 ; return ch; } int main() { int i = 0; char arr[20]; char* ret = my_strcpy(arr,"hello world"); printf("%s\n",ret); system("pause"); return 0; }运行结果：
2.模拟实现strcmp
//模拟实现字符串比较函数strcmp #include <stdio.h> #include <stdlib.h> int mystrcmp(char *str1, char *str2) { while(*str1 || *str2) { if(*str1 == *str2) { str1++; str2++; } else { return -1; } } if(*str1 == *str2) { return 1; } else { return -1; } } int main() { char arr1[] = "hello"; char arr2[] = "hello world"; int ret = mystrcmp(arr1, arr2); if(ret == 1) { printf("这两个字符串相同\n"); } else { printf("这两个字符串不同\n"); } system("pause"); return 0; } 运行结果：
3.模拟实现strcat
//模拟实现字符串粘贴函数strcat #include <stdio.h> #include <stdlib.h> char* mystrcat(char *str1, char *str2) { char *p1 = str1; char *p2 = str2; while(*p1) { p1++; } while(*p2) { *p1 = *p2; p1++; p2++; } *p1 = '\0'; return str1; } int main() { char arr1[100] = "hello "; char arr2[] = "world"; char *arr = mystrcat(arr1, arr2); printf("%s\n",arr); system("pause"); return 0; }运行结果：
