c - Calculation function returns 0 whatever the user puts in after creating header files -

im buisy learning myself c more or less not having previous programming exprerience. have made simple program in c , worked more or less. not perfect or anywhere near fine learning.

but got bug in program , can't find nor know how bug track such thing (yet).

i use github learn , perhaps guys can see did wrong in function or headers. (the thing try understand how header files work in c.) , teaches me make propper commits :/ .....

https://github.com/greendweller/myfirstprogram

the bug program wil not calculate anymore. accepts user input shows 0 result , cant figure out why. calclation functions in ../circle/circlefunctions.c

i hope enough information or need post code here. please let me know.

edit okay have post code directly, no problem:

circlefunctions.c

#include "circlefunctions.h" #define pi 3.14  float   diameter; double  radius; double  surface; double  outline;  void circle_functions() {     radius   = diameter / 2;     surface  = pi * (radius * radius);     outline  = 2 * pi * radius; } 

circlefunctions.h

extern float  diameter; extern double radius; extern double surface; extern double outline;  void circle_functions(); 

main.c

    #include <stdio.h>      #include "menu/menu.h"     #include "circle/circlemenu.h"     #include "circle/circlefunctions.h"     #include "input/input.h"        int main(void) {     while(1) {     menu();     switch(menu_user_input()) {     case 1:          info_top();         cir_user_input();         circle_functions();         info_bottom();         break;      case 2:         system("cls");      case 3:         system("cls");      case 9:         system("cls");         break;      case 0:         return(0); }  }  return 0; } 

input.c

#include <stdio.h> #include "input.h"  int menu_user_input() {     int number;     scanf(" %d", &number);     return number; }  float cir_user_input() {     float diameter;     scanf(" %e", &diameter);     return diameter; } 

input.h

int   menu_user_input(); float cir_user_input(); 

i can post rest if needed guess enough?

edit2

i think found a/the solution:

i set variable diameter 2 times. in input.c , circlecalculations.c , resets value think. or left blank input.h never included in circlecalculations.c.

you using global variables, (almost) bad design. current calculation function:

void circle_functions() {   radius = diameter / 2;   surface = pi * (radius * radius);   outline = 2 * pi * radius; } 

much better pass in needed inputs , return result:

double circle_functions(double diameter) {   double radius = diameter / 2;   double surface = pi * (radius * radius);   double outline = 2 * pi * radius;   return outline; }