So what's the difference between writing a function after main and writing a function before main?Code:#include<stdio.h> amount(int a, int b); int main(void) { ... amount(a,b) ... } amount(int a, int b) { ... } OR #include<stdio.h> amount(int a,int b); amount(int a, int b) { ... } int main(void) { ... amount(a,b) ... }
Welcome to the forum.
The difference is that you do need line 21, the prototype (declaration). The implementation of the function is the definition of the function.
Check the basics of functions (check the link only if you know some basic things about pointers).
Code - functions and small libraries I use
It’s 2014 and I still use printf() for debugging.
"Programs must be written for people to read, and only incidentally for machines to execute. " —Harold Abelson
In the second case, you do not need amount(int a,int b); (see link below)
You have already informed the compiler of what is to come. So, when you call the function inside main, the program knows what your talking about.
In the first case, that is called function prototype. Your telling the compiler of what is to come. Hence, when you call the function inside main, it knows what should be expected hence what it should do.
Please also see second link. That is an incorrect way to call functions
http://i42.tinypic.com/2hf85r5.png
http://i41.tinypic.com/2zreu6w.png
