getop.c

Multi-module programs and MAKE

#include <stdio.h>
#include <ctype.h>
#include "getop.h"
#include "getch.h"

/* getop: get next operator or numeric operand */
/* note simplification allowed for ints--no decimal point handling */
int getop(char s[])
{
    int i=0, c;

    while ((s[0] = c = getch()) == ' ' || c == '\t')
	;
    s[1] = '\0';
    if (!isdigit(c))
	return c;       /* not a number */
    else 
	while (isdigit(s[++i] = c = getch()))
	    ;
    s[i] = '\0';
    if (c != EOF)
	ungetch(c);
    return NUMBER;
}