i need help filling in the functions and the main program. i have to fill in code where it says fill in code

#include // Copies the C string pointed by source into the array pointed by destination, // including the terminating character (and stopping at that point). // To avoid overflows, the size of the array pointed by destination shall be long enough to contain // the same C string as source (including the terminating null character), and should not overlap // in memory w/ source. harstrcpy-nccare herconst char. p) { // Copies the first num characters of source to destination. If the end of the source C string (which is signaled // by a null-character) is found before num characters have been copied, destination is padded with zeros char* strncpy_(char* q, const char* p, size t n) // fill in code here // Returns the length of the C string str. // The length of a C string is determined by the terminating null-character: A C string is as long as the number of characters // between the beginning of the string and the terminating null character (without including the terminating null character itself) Il size_t strlen_(const char* p) f // fill in code here // Appends a copy of the source string to the destination string. The terminating null character in destination is overwritten by the first character of source, and a null-character is included at the end of the new string formed // by the concatenation of both in destination. destination and source shall not overlap char* strcat_(char* s, const char* ct) t // fill in code here