Question

所以我使用fscanf来读取文件，我正在尝试将这些字符串放入数组中。它似乎工作，但我只是将最后一个字符串放入我的数组。当我尝试打印它时，我只打印我最后一个字符串的字符。我没有包含我的方法，因为它不会影响fscanf所做的事情，以防任何人感到困惑。此外，我的CMDLINE文件具有以下字符串foo barr tar 526-4567 456-8792。

输出是：

456-8792
56-8792
6-8792

等...

以下是代码：

int main (int argC, char *argV[]) {
    FILE *fp;
    int index;
    int ret;
    char str[1000];

    //Need at least 2 files to begin program
    if (argC < 3) {
        fprintf(stderr, "Usage: %s file\n", argV[0]);
        exit(1);
    }//if statemtn

    //check to see if the CMDLINE file is in the arguements
    ret = scanC(argC, argV);

    //if no CMDLINE file is found, print error and exit
    if (ret == 1) {
        fprintf(stderr, "you must provide a CMDLINE file\n");
        exit(1);
    }

    //iterate and open CMDLINE file and read from it
    for (index = 0; index < argC; index++) {
        if (strcmp(argV[index], "CMDLINE") == 0) {
            fp = fopen(argV[index], "r");
            //error check
            if (fp == NULL) {
                fprintf(stderr, "Counld not open file %s\n", argV[index]);
                exit(1);
            }//if statment

            //read from fscanf and put it's arguements into an array
            while (!feof(fp)) {
                char *p2 = str;
                //scan the strings of the file into str array
                while (fscanf(fp, "%s", p2) != EOF) {
                    p2++;
                }//while loop 2
            }//while lop 1

            //close the file for it is not needed to be open anymore
            fclose(fp);
        }//if statement
    }//for looop

    char *p;
    p = str;
    int j;
    for (j = 0; j < strlen(str); j++) {
        printf("%s\n", p);
        p++;
    }
    return 1;
}

Answer 1

char *p;
p = str;
int j;
for (j = 0; j < strlen(str); j++) 
{
    printf("%s\n", p);
    p++;
}

您有一个字符串，例如"abcd"，您可以将其打印为printf("%s\n", str);而不是从不同的偏移量开始打印相同的字符串。结果如下：

abcd
bcd
cd
d

也许你对“字符数组”和“数组字符串”

感到困惑

//This will reserve 100 character arrays, or 100 strings
char *arr[100];

int count = 0;
while (fscanf(fp, "%999s", str) == 1)
{
    arr[count] = malloc(strlen(str) + 1);
    strcpy(arr[count], str);
    count++;
    if (count == 100)
        break;
}

int i;
for (i = 0; i < count; i++) 
    printf("%s\n", arr[i]);

在实际应用程序中，您使用malloc和realloc来分配足够大的字符串数组来读取文件。

Answer 2

您可以使用标记设置“当前字符”：

char *p2 = str;
size_t k = 0;
size_t pos = 0;
//scan the strings of the file into str array at position pos
while((k = fscanf(fp, "%s", p2 + pos)) != EOF){
    // update pos
    pos += k;
    p2++;
}//while loop 2

这将使整个文件存储在您的字符串中提供它不到1000个字符！否则只需在while循环中添加一个安全措施。

如何使用fscanf将字符串放入数组？

2 个答案: