函数里的取模有点问题

愚蠢的萝卜 2014-08-19 09:35:36

//逆波兰计算器主函数
#include<stdio.h>
#include<stdlib.h>
#include<math.h>

#define MAXOP 100
#define NUMBER '0'

int getop(char s[]);
void push(double);
double pop(void);

main()
{
int type;
double op2;
char s[MAXOP];

while((type = getop(s)) != EOF){
switch (type){
case NUMBER:
push(atof(s));
break;
case '+':
push(pop() + pop());
break;
case '*':
push(pop() * pop());
break;
case '-':
op2 = pop();
push(pop() - op2);
break;
case '/':
op2 = pop();
if(op2 != 0.0)
push(pop() / op2);
else
printf("error: zero divisor\n");
break;
case '%':
op2 = pop();
if(op2 != 0.0) //此处取模
push(fmod(pop(), op2)) ;
else
printf("error:zero divisor for \n");
break;
case '\n':
printf("\t%.8g\n", pop());
break;
default:
printf("error: unknow command %s\n", s);
break;
}
}
return 0;
}

//getch 和 ungetch 函数
#include<stdio.h>
#define BUFSIZE 100

char buf[BUFSIZE];
int bufp = 0;

int getch(void)
{
return (bufp > 0) ? buf[--bufp] : getchar();
}
void ungetch(int c)
{
if(bufp >= BUFSIZE)
printf("ungetch : too many characters");
else
buf[bufp++] = c;
}

//getop函数
#include<ctype.h>
#include<stdio.h>
#define NUMBER '0'

int getch(void);
void ungetch(int);

int getop(char s[])
{
int i, c;

while( (s[0] = c = getchar()) == ' ' || c == '\t' )
;
s[1] = '\0';
if( !isdigit(c) && c != '.' && c != '-' )
return c;
i = 0;
if(c == '-')
if(isdigit(c = getch()) || c == '.')
s[i++] = c;
else {
if(c != EOF)
ungetch(c);
return '-';
}
if( isdigit(c) )
while (isdigit (s[++i] = c = getch()))
;
if(c == '.')
while(isdigit (s[++i] = c = getch()))
;
s[i] = '\0';
if(c != 'EOF')
ungetch(c);
return NUMBER;
}

//push 和 pop函数
#define MAXVAL 100
int sp = 0;
double val[MAXVAL];

void push(double f)
{
if(sp < MAXVAL)
val[sp++] = f;
else
printf("error: stack full, can't push %g\n", f);
}

double pop(void)
{
if(sp > 0)
return val[--sp];
else {
printf("error: stack empty\n");
return 0.0;
}
}

取模的话输入 7 2 % 结果是正常的是1；

输入 7.0 2.0 % 就不对了显示op2是等于0.0的
只要加一个 .0 都是等于0.0了