Anyone know how to put string input in language C?
Simple way: using a character array
Advancing it: use pointers and a dynamic array of characters
Even more advanced-nes: make a linked link class, or rather, the equivalent since IIRC C doesn't use classes like C++ does, where the data member is a character.
And use assert as a lazy-ish means of validation - make the program blow up in the face of whomever mis-uses it.