Question

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string>
#include <iostream>

FILE *pfile;
using namespace std;

string temp_string;
string reserved[25] = {"AND", "CALL", "DECLARE", "DO", "ELSE", "ENDDECLARE", "ENDFUNCTION", "ENDIF", "ENDPROCEDURE", "ENDPROGRAM", "EXIT", "FALSE", "FOR", "FUNCTION", "IF", "IN", "INOUT", "NOT","OR", "PROCEDURE", "PROGRAM", "RETURN", "THEN", "TRUE", "WHILE"};


int main(void)
{
    pfile = fopen("hello.cel", "r");
    char cha, temp_token[30], temp;
    int count = 0, check = 1, i;
    cha = fgetc(pfile);
    while (cha != EOF)
    {
        if(isalpha(cha) || cha ==  _ )
        {
            temp_token[0] = cha;
            count = 1;
            cha = fgetc(pfile);
            while(isdigit(cha) || isalpha(cha) || cha ==  _ )
            {
                if(count < 30)
                {
                    temp_token[count] = cha;
                    count++;
                }
                cha = fgetc(pfile);         
            }
            count--;
            for(i = 0; i <= count; i++)
            {
                temp_string += temp_token[i];
            }
            cout << temp_string;
            for(i = 0; i < 25; i++)
            {
                if(temp_string == reserved[i])
                {
                    printf(": RESERVED
");
                }
                else
                {
                    printf(": ALPHA
");
                }
            }

            cha = ungetc(cha, pfile);
            count = 0;
        }
        fclose(pfile);
}

I have a problem with the comparison statement between the reserved[i] and temp_string strings. I cannot succeed printing "RESERVED", it always print "ALPHA". To your knowledge, this is a program that gets each character from a file (hello.cel) and prints the type of each token.

EDIT:诱因是临时储存词。添加以下文字:<代码>temp_string += 页: 1

Answer 1

不宣布节奏。

Have you declared temp_string as string? For me it prints Reserved for keywords.

Answer 2

坡道的尾部有线chy;你有一条缺失的<条码>><>>>>和<条码>ungetc()像完全错做的。你们需要改变

            cha = ungetc(cha, pfile);
            count = 0;
        }
        fclose(pfile);
}

纽约总部

        }
        cha = fgetc(pfile);
    }
    fclose(pfile);
}

Also declare temp_string just before the loop that populates it (or, if you really want it 纽约总部be global for some reason, call clear() at that point). Better still, initialise it from the buffer, after removing the pointless count--:

std::string temp_string(temp_token, temp_token+count);

甚至更糟的是,摆脱了临时缓冲,并且正如你所读的那样,建造了扼子:

        std::string token(1, cha);
        cha = fgetc(pfile);
        while(isdigit(cha) || isalpha(cha) || cha ==  _ )
        {
            if(token.size() < 30)
            {
                token.push_back(cha);
            }
            cha = fgetc(pfile);         
        }

最后,在检查所有保留标记后,只有打印的<代码>ALPHA:

bool is_reserved = false;
for(i = 0; i < 25; i++)
{
    if(token == reserved[i])
    {
        is_reserved = true;
        break;
    }
}
printf(": %s
", is_reserved ? "RESERVED" : "ALPHA");

Here是一个不太破碎的版本。

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