The program stops abruptly

There are a load of problems here.
You're passing a constant string to a function and then trying to write into it. That isn't allowed, any more than I can change your own name by writing mine over the top on your birth certificate!
It's because you declare a pointer to a character variable called newi but you don't give it a value at all. So when you try to copy the string that the function returns into it, it hasn't got anywhere to put it.

Try this:

#include<stdio.h>
#include<string.h>

char* newme(char* input1);
int main()
{
    char data[100];
	char newi[100];
	strcpy(newi,newme(data));
	return 0;
}
char* newme(char* input1)
 
{
float p=22.9999,w=99.83234,r=333.523422;
	sprintf(input1," %.2f,%.2f,%.2f",p,w,r);
	printf("%s",input1);
	return input1;
}

It should work better.

You call function newme passing a pointer to a constant string ("platue..."). That function then tries to write into that string using sprintf and thus fails. You need to create a buffer large enough to hold the returned string and pass that, or allocate it inside the newme function and return its pointer to the caller. You also need to allocate a buffer to newi before your call to strcpy.

Here is links to references books on C and C++ by the authors of the languages. Note than C is the ancestor of C++, so knowing C is always useful with C++.
The C Programming Language - Wikipedia, the free encyclopedia[^]
https://hassanolity.files.wordpress.com/2013/11/the_c_programming_language_2.pdf[^]
http://www.ime.usp.br/~pf/Kernighan-Ritchie/C-Programming-Ebook.pdf[^]

C++ Programing Language[^]

Have a good lecture, looks you need it.