c - 为什么 strtok() 不从行中选择 '?' 字符？

Question

下面是我在 codeblocks 版本 13:12 中的代码。它没有评论，因为我很快放下它在这里问我失去了我的头发!我担心的是，我希望我的 char * 目标是 /cat.html?name=image 但我只得到 /cat.html!

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

int main() {
    const char *space = " ";
    const char *marker = "?";
    const char line[] = { "GET /cat.html?name=image HTTP/1.1" };
    int n = strlen(line), i, j, k, a;
    char string[n + 1];

    for (i = 0; i <= n; i++) {
        string[i] = line[i];
        string[n] = '\0';
    }
    printf(" line has %i characters \n\n", n);
    char *method = strtok(string, space);
    char *target = strtok(NULL, space);
    char *version = strtok(NULL, space);

    char *abs_path = strtok(target, marker);
    char *query = strtok(NULL, marker);

    printf("\n line is:%s \n"
           "\n method is:%s \n"
           "\n target is:%s \n"
           "\n version     is:%s \n"
           "\n abs_path is:%s \n"
           "\n query is:%s \n\n\n",
           line, method, target, version, abs_path, query);

    int l = strlen(target);
    if (strcmp(method, "GET") != 0) {
        printf("wrong method error 405 \n\n");
    }

    printf(" target contains %i characters \n\n", l);
    for (j = 0; j <= l; j++) {
        if (target[0] != '/') {
            printf("wrong target does not start with \\/error 501\n\n");
        }
        if (target[j] == '"') {
            printf("wrong target error 400 has a \" \n\n");
        }
    }
    if (strchr(abs_path, '.') == NULL) {
        printf("wrong absolute path has no \. \n\n");
    }
    if (strncmp(version, "HTTP/1.1", 8) != 0) {
        printf("wrong version not HTTP/1.1 error 505 \n\n");
    }
    return 0;
}

Answer 1

char * method = strtok(string, space);
char * target = strtok(NULL, space);
char * version = strtok(NULL, space);

在这些行之后，target 确实确实具有值 "/cat.html?name=image"。问题是您随后在 target 上再次调用 strtok，这将修改字符串:

abs_path = strtok(target, marker);

在该行之后，target 将具有值 "/cat.html"

如果您想保留 target 的原始值，您需要在第二个 strtok 之前复制它。在目标上。