Sorry left that out, shown here. Style will have to develop with experience. I think the value of temp * 10 = 0 when declared as 'int'.

int getdec(unsigned char dpoint, unsigned char alwneg, unsigned char angent)
// dpoint, alwneg, and angent are flags that are not implemented yet
{
// local variables
int decimal;		// return value
int temp;		// temporary value
int key;
...
...
// initialize variables
decimal = 0;		// clear return value
temp = 0;		// clear temp value
negent = 0;		// negative not entered yet
dpent = 0;		// decimal not entered yet
n2big = 0;
alwneg;
angent;
...
	key = 0;
	while (key == 0)
		{
		key = getkey();        // get key code from keypad
		}
...
a switch/case statement assigns the correct numeric value to 'key'
...
	if ((key >= 0) & (key <= 9))            // if key is numeric
		{
		putchar(key + 48);		// display ascii value
		temp = temp * 10 + key;		// tally it
                }
return(temp);
}