Question

我一直收到错误，我不知道为什么。由于某种原因，编译器认为char指针p是一个整数。我的代码的相关部分是：

int main(int argc, char **argv) {
    char *p;
    FILE *fd = fopen("words.txt", "r");
    unsigned char *iv = (unsigned char *)"0000000000000000";
    unsigned char *plaintext = (unsigned char *)"This is a top secret";
    unsigned char *real_ciphertext = (unsigned char *)"8d20e5056a8d24d0462ce74e4904c1b513e10d1df4a2ef2ad4540fae1ca0aaf9";
    //unsigned char key[128];
    unsigned char ciphertext[128];  
    int ciphertext_len;

    while ((p = nextword(fd)) != NULL) {    
        int l;
        /* append space characters to key to make sure it is 16 characters long*/
        while ((l = strlen(p)) < 16) {
            p[l + 1] = ' ';
            p[l + 2] = '\0';
        }
        /* Encrypt the plaintext with the key */
        ciphertext_len = encrypt(plaintext, strlen((char *)plaintext), p, iv, ciphertext);

        if (strcmp(real_ciphertext, ciphertext) == 0)
            printf("The key is:%s", p);         
    }

    EVP_cleanup();
    ERR_free_strings();
    fclose(fd);
}

 //
 // gets the next word from the list of words
 //
 #define MAXWORD 200
 // It returns the next word nullterminated from fd.
 // If there are no more more words it returns NULL. 
 unsigned char word[MAXWORD];
 unsigned char c;

 char *nextword(FILE *fd) {
    int wordLength = 0;

    while ((c = fgetc(fd)) != EOF) {
        if ((c != ' ') && (c != '\n') && (c !='\t') && (c !='\r')) {
            word[wordLength] = c;
            wordLength++;
        } else
        if (wordLength > 0) {
            word[wordLength] = '\0';           
            return word;
        }
    }

    if (wordLength > 0) {
        word[wordLength] = '\0';
        return word;
    } else
        return NULL;
}

从这段代码中，我编译并得到错误：

findkey.c：在函数'main'中：

findkey.c：25：11：警告：赋值使用整数指针   没有演员

while（（p = nextword（fd））！= NULL）

findkey.c：顶级：

findkey.c：65：8：错误：'nextword'char * nextword（FILE * fd）的冲突类型

findkey.c:25:13：注意：先前隐含的'nextword'声明是   这里（（p = nextword（fd））！= NULL）

Answer 1

由于在 main之后声明/定义，nextword，编译器将其签名默认为int nextword(void)

在main之前定义它或在main之前添加前向声明：

char * nextword(FILE * fd);

当然，打开警告并实际上读取和修复它们没有比这更好的了。

gcc -Wall -Werror -c file.c

我的char指针被gcc解释为整数

1 个答案: