C program not displaying value - c

Question

when i call my multi() it will calculate the binary number just fine, but won't calculate the adding(). If i switch the two in order, it will calculate the adding() and not calculate the multi(). Is there a reason why the second function call isn't displaying its value? It will print the printf, but not the value. Any help would be great.
#include <stdio.h>
long binary1, binary2, binary3, binary4, multiply = 0;
int binaryproduct(int, int);
int digit, factor = 1;
int multi();
int adding();
int main()
{
binary3 = binary1;
binary4 = binary1;
printf("Enter the first binary number: ");
scanf("%ld", &binary1);
printf("Enter the second binary number: ");
scanf("%ld", &binary2);
multi();
printf("\n");
adding();
}
int adding()
{
int i = 0, remainder = 0, sum[20];
while (binary3 != 0 || binary4 != 0) {
sum[i++] =(binary3 % 10 + binary4 % 10 + remainder) % 2;
remainder =(binary3 % 10 + binary4 % 10 + remainder) / 2;
binary1 = binary3 / 10;
binary2 = binary4 / 10;
}
if (remainder != 0) {
sum[i++] = remainder;
}
--i;
printf("Sum of two binary numbers: ");
while (i >= 0) {
printf("%d", sum[i--]);
}
return 0;
}
int multi()
{
while (binary2 != 0) {
digit = binary2 % 10;
if (digit == 1) {
binary1 = binary1 * factor;
multiply = binaryproduct(binary1, multiply);
} else {
binary1 = binary1 * factor;
}
binary2 = binary2 / 10;
factor = 10;
}
printf("Product of two binary numbers: %ld", multiply);
return 0;
}
int binaryproduct(int binary3, int binary4)
{
int i = 0, remainder = 0, sum[20];
int binaryprod = 0;
while (binary1 != 0 || binary2 != 0) {
sum[i++] =(binary1 % 10 + binary2 % 10 + remainder) % 2;
remainder =(binary1 % 10 + binary2 % 10 + remainder) / 2;
binary1 = binary1 / 10;
binary2 = binary2 / 10;
}
if (remainder != 0) {
sum[i++] = remainder;
}
--i;
while (i >= 0) {
binaryprod = binaryprod * 10 + sum[i--];
}
return binaryprod;
}

Answer 1

Your globals aren't being initialized. In you adding() function you use:
binary1 = binary3/10
binary2 = binary4/10
and in the binaryproduct function you have two local ints named binary3, binary4 that you don't use.
You should be using unique names, initializing you variables, use local variables in places where globals are unnecessary.