c - 使用 getopt() 时无法分配 optarg

Question

我无法将 optarg 分配给 inFilename 和 outFilename。该错误表明发生了不兼容的类型错误。如果这是一个小错误，请原谅我，我大约一周前开始学习 C。

编辑:我使用过 strncpy 但出现段错误。

编辑:这是我打算如何使用它:

./sortfile -i 输入.txt -o 输出.txt

     int main(int argc, char *argv[]) {
        char c;

        const int MAX_FILENAME_LEN = 256;
        const int MAX_NUMBERS      = 100;

        int xFlag = 0;
        int yFlag = 0;

        char inFilename[MAX_FILENAME_LEN];
        char outFilename[MAX_FILENAME_LEN];
        int  *numbers;  // number array: to be dynamically allocated
        int  count;
        int  exitValue = 1;

        //printf("Enter the input file name: ");
        //scanf("%s", inFilename);

        while ((c = getopt(argc, argv, "ioxy")) != -1) {
                switch (c) {
                        case 'i':
                                strncpy(inFilename, optarg, sizeof(inFilename) - 1);
                                break;
                        case 'o':
                                strncpy(outFilename, optarg, sizeof(outFilename) - 1);
                                break;
                        case 'x':
                                xFlag = 1;
                                break;
                        case 'y':
                                yFlag = 1;
                                break;
                        case '?':
                                fprintf(stderr, "Unrecognized option!\n");
                                break;
                }
        }

        if (!inFilename || !outFilename) {
                fprintf(stderr, "Must have -i and -o option!\n");
                exit(0);
        }


        numbers = (int *) malloc(MAX_NUMBERS * sizeof(int)); 

        count = readNumbers(numbers, inFilename);

        if (count >= 0) {
                //printf("Enter the output file name (will be created/overwitten): ");
                //scanf("%s", outFilename);

                printArray(numbers, count);
                bubbleSort(numbers, count, true);

                printArray(numbers, count);
                writeNumbers(numbers, count, outFilename);
       }

        free(numbers);

        return exitValue;
}

这是更改前的程序。这个程序有效。

int main(void) {
const int MAX_FILENAME_LEN = 256;
const int MAX_NUMBERS      = 100;

char inFilename[MAX_FILENAME_LEN];
char outFilename[MAX_FILENAME_LEN];
int  *numbers;  // number array: to be dynamically allocated
int  count;
int  exitValue = 1;

printf("Enter the input file name: ");
scanf("%s", inFilename);


numbers = (int *) malloc(MAX_NUMBERS * sizeof(int)); 

count = readNumbers(numbers, inFilename);

if (count >= 0) {
    printf("Enter the output file name (will be created/overwitten): ");
    scanf("%s", outFilename);

    printArray(numbers, count);
    bubbleSort(numbers, count, true);

    printArray(numbers, count);
    writeNumbers(numbers, count, outFilename);

    exitValue = 0;
}


free(numbers);

return exitValue;

Answer 1

这个:

getopt(argc, argv, "ioxy")

告诉 getopt() 四个选项，i、o、x 和 y，它们都不带参数。这就是为什么从 optarg 获取这些参数的任何尝试都失败了，因为它们不存在。

你需要的是:

getopt(argc, argv, "i:o:xy")

告诉 getopt() 你的 i 和 o 选项应该有参数