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Imports:
#include 
   
    
#include 
    
     
#include 
     
      
Include necessary headers for string manipulation
Variables:
char ch1[] = { 'c', '+', '+' };
char ch2[] = { 'c', '+', '+', '\0' };
char* ch3 = "myC++";
char* ch4 = "good idea";
Function prototypes:
int strlen_new(const char* src);
char* strcat_new(char* strD, const char* strS);
void* memcpy_new(void* dst, void* src, size_t n);
void* memmove_new(void* dst, void* src, size_t n);
Implementing custom string functions:
- strlen_new: Counts characters in a string
- strcat_new: Concatenates two strings
- memcpy_new: Copies memory block
- memmove_new: Handles memory block moving with proper bounds checking
Testing functions:
int main()
{
    int str_len = 0;
    char* mem_src = "the src test memcpy";
    char mem_dest[29] = "another hello";
    char* mv_src = "the src test memmove";
    char mv_dest[20];
    
    // Testing memcpy
    printf("Test memcpy result: %s\n", memcpy(mem_dest, mem_src, 20));
    
    // Testing memmove
    printf("Test memmove result: %s\n", memmove_new(mv_dest, mv_src, 10));
    
    // String length test
    str_len = strlen_new(ch3);
    printf("Length of ch3: %d, string value: %s\n", str_len, ch3);
    
    return 0;
}
     
    
   

Running results: memcpy test output: the src test memcpy memmove test output: the src tegood idea String length: 5, string value: good idea Comparison result: 6 (or -6, depending on comparison direction)

Program execution complete and returned 0.