making string by using strncat in c code example

Example 1: c concatenate strings

char str[80];
strcpy(str, "these ");
strcat(str, "strings ");
strcat(str, "are ");
strcat(str, "concatenated.");

Example 2: strncat in c

Input:  src = "world"
        dest = "Hello "
Output: "Hello world"

Input:  src = "efghijkl"
        dest = "abcd"
Output: "abcdefghi"