Question

我正在尝试添加具有sin，pow和exp函数功能的能力到我的计算器。我正在进行分段错误＆＃34;当我尝试编译时。我认为问题出在＆lt; void trigFunction（char s []）＆＃39;功能

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>

#define MAXOP 100
#define NUMBER '0'
#define TRIG 1 /**/
#define TRUE 1
#define FALSE 0

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

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

    printf("\nEnter numbers below in the following format\nwith a space between each:\n");
    printf("\tnum1 num2 operator\n");
    printf("You may use the operators:\n");
    printf("plus(+), minus(!), divide(/), multiply(*),\npercentage(%), swap(~), sine(S), exp(E), and pow(P)\n");

    while((type = getop(s)) != EOF)
    {
        switch(type)
        {
            /*other cases I have taken out to make code shorter*/

            case TRIG: /*case for sin, exp, pow functions*/
                trigFunction(s);
                break;


            case '\n':
                printf("\t%.8g\n", pop());/*prints out soultion*/
                break;
            default:
                printf("error: unknown command %s\n", s);
                break;
        }
    }
    return 0;
}

void trigFunction(char s[])
{
    double op2;

    if(0 == strcmp(s, 'S'))/*strcmp() function compares the string pointed to by s1 to the string pointed to by s2.*/
        push(sin(pop()));/*pushes the sine of pop() onto the stack*/
    else if(0 == strcmp(s, "E"))
        push(exp(pop()));
    else if(0 == strcmp(s, "P"))
    {   
        op2 = pop();
        push(pow(pop(), op2));
    }   
    else
        printf("I don't know what you mean by %s, but I may \nself destruct if you don't enter         \na correct operator\n", s);
}

#define MAXVAL 100

int sp = 0;
double val[MAXVAL];

void push (double f)
{
    if(sp < MAXVAL)
    {
        val[sp++] = f;
    }   
    else
    {
        printf("error: stack full, cant push %g\n",f);
    }   
}

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

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

int getop(char s[])
{
  int i = 0, c, next;

  while ((s[0] = c = getch()) == ' ' || c == '\t')/*skips white space*/
    ;
  s[1] = '\0';

  if(isalpha(c))
   {
      i = 0;
      while(isalpha(s[i++] = c ))
         c = getch();     
      s[i - 1] = '\0';
      if(c != EOF)
         /*ungetch(c);*/
      return TRIG;
   }

  if(!isdigit(c) && c != '.' && c != '-')/* not number. may contain minus*/
    return c; 
  if(c == '-')
  {
    next = getch();
    if(!isdigit(next) && next != '.')
    {
        ungetch(next);/*puts next char in buffer*/
        return c;
    }    
    c = next;
  }
  else
    c = getch();

  while(isdigit(s[++i] = c))
            c = getch();
    if(c == '.')                     /* Collect fraction part */
        while(isdigit(s[++i] = c = getch()))
                        ;
    s[i] = '\0';
    if(c != EOF)
        ungetch(c);/*puts c in buffer*/
    return NUMBER;
}

#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\n");
    }
  else
    {
        buf[bufp++] = c;
    }
}

Answer 1

void trigFunction(char s[])
{
    double op2;

    if(0 == strcmp(s, 'S'))/*strcmp() function compares the string pointed to by s1 to the string pointed to by s2.*/
        push(sin(pop()));/*pushes the sine of pop() onto the stack*/
    else if(0 == strcmp(s, "E"))
        push(exp(pop()));
    else if(0 == strcmp(s, "P"))
    {   
        op2 = pop();
        push(pow(pop(), op2));
    }   
    else
        printf("I don't know what you mean by %s, but I may \nself destruct if you don't enter         \na correct operator\n", s);
}

好吧，我们来看看：

if(0 == strcmp(s, 'S'))

应该是

if(0 == strcmp(s, "S"))

当您将单个char传递给期望char *的函数时...

这应该可以修复您的代码。

你可以进一步简化它。在所有情况下，你只看第一个角色，所以你可以这样做：

if (s[0] = 'S')

并将char与char进行比较，但如果您想稍后展开，则无法提供帮助，例如将as用于arcsine。

旁注：
有趣的是知道主要的三个trig函数是 sin，exp和pow。 我多年来一直在做错 sin，cos和tan。
（我认为它们只是占位符）

C中的trig函数的分段错误错误

1 个答案: