如何使用字符、数组和指针在 c 中写这个函数？ [电话暂停]

I have already tried it and i know it is a bit rude to ask but I am really new to c... please someone help

1.

void strcpy_upper(char *dest, const char *src); 

which copies string src into string dest converting all lowercase letters in a text string to uppercase.

2.

void strremdup(char* dest, const char* src); 

which copies the string src into string dest ignoring repeated adjacent characters.

3.

void swap_random(char* str); 

which swaps characters randomly in string src.

my attempt at the first one :

 void mystrcpy(char *dest, const char *src)
 {
      int i;
      for (i = 0; src[i] != '\0'; i++)
      {
           dest[i] = src[i];
      }
      dest[i] = '\0';
      printf("%c", *src);
 }

 int main()
 {
      char P[5] = "hell";
      char K[5];
      mystrcpy(P, K);
      system("pause");
      return 0;
 }

You're passing the parameters in wrong order, mystrcpy() should be called as:

mystrcpy(K, P);

since you're copying from K to P

Also, to print string use %s

printf("%s", dest);