c - 为什么不打印连字符 (-)？

Question

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

int main(int argc, char* argv[])
{
        FILE* fp = fopen(argv[1],"r");
        char* ptr;
        int size;
        while(1){
                int scanfinteger = fscanf(fp,"%d",&size);
                ptr = (char*)malloc((size+1)*sizeof(char));
                if(scanfinteger != 1){
                        int result = fscanf(fp,"%s",ptr);

                        printf("ptr:[%s]\n",ptr);
                        if(result == EOF)
                                break;
                }
        }
        return 0;

}

input_file(argv[1]) 包含这个

10 This
10 is
10 buffers
10 -
10 hi
10     -hello

我的程序的输出

ptr: [This]
ptr: [is]
ptr: [buffers]
ptr: [10]
ptr: [hi]
ptr: [hello]

我不明白为什么连字符会被消耗掉。有人见过这个问题吗？谢谢!

Answer 1

如果我可以建议不同的解决方案，我建议您阅读行，然后解析这些行。

也许是这样的:

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

int main(int argc, char* argv[])
{
    // First make sure you have enough arguments
    if (argc < 2)
    {
        printf("Need an argument!\n");
        return 1;
    }

    // Open the file, and make sure we succeeded
    FILE *fp = fopen(argv[1], "r");
    if (fp == NULL)
    {
        printf("Failed to open the file %s: %s\n", argv[1], strerror(errno));
        return 1;
    }

    // Now read the file, one line at a time
    char line[100];
    while (fgets(line, sizeof line, fp) != NULL)
    {
        // Now we have a line, attempt to parse it
        int value;
        char string[100];
        if (sscanf(line, "%d %99s", &value, string) != 2)
        {
            printf("Failed to parse the current line\n");
            break;  // Break out of the loop
        }

        printf("Read value %d, string '%s'\n", value, string);
    }

    // All done, or we had an error (should probably check that)
    // Anyway, close the file and end the program
    fclose(fp);
}

---

您当前代码的问题(这似乎不是您运行的实际代码)是您仅在读取数字失败时才读取字符串。

我不知道产生该输出的实际代码有什么问题。但不知何故，它不同步。这可以看出，您将一行中的数字作为字符串读取。