Please solve this in C programming language as early as possible.

Suppose, you are trying to encrypt a string for security purpose. Write a program that can take a string from the user and then create a function that can replace all the vowels to its immediate next letters. Print the modified string. Dont use any Library function.

Use this function: void str_modify(char *p); (6)

Example: Input string: i love Bangladesh.

Modified string: j lpvf Bbnglbdfsh