Question

练习：使用Obj C和C，创建一个命令行应用程序，它将： •以下列格式获取带有笛卡尔坐标的txt文件：

(2;9)
(5;6)
...

•（其他技术要求）

问题：处理输入数据的最佳方法是什么？ C具有fscanf fgetc和fgets等功能。如果我理解正确 - 我们不能使用fgets - 因为它适用于不是整数/浮点数/双打的字符。它会读取每个角色。我们不能使用fgetc - 因为它只返回转换为int的1个字符（流中的下一个字符）。

我有几种方法，但到目前为止还没有。首先 - 使用for循环。我想先计算坐标对的数量，然后将.txt文件中的数据整理成2个数组，用于x和y坐标：

float xCoordinate [MAXSIZE] = {0.0};
float yCoordinate [MAXSIZE] = {0.0};

float x;
float y;
FILE *handle;
handle = fopen ("points.txt", "r");
int ch;
int n;

ch=fgetc(handle)!=EOF; //error. This will read every character including ( ) and ; . 
//Maybe I omit this loop condition? 

for (n=0; n<=ch ; (fscanf(handle, "(%f;%f)", &x, &y) )
{
xCoordinate [n+1] = x;
yCoordinate [n+1] = y;
}

Answer 1

只要fscanf返回两个成功读取的项目并且n小于MAXSIZE，就应该读取该文件。

float xCoordinate [MAXSIZE] = {0.0};
float yCoordinate [MAXSIZE] = {0.0};

float x;
float y;
FILE *handle;
int n = 0;

if ( ( handle = fopen ("points.txt", "r")) == NULL) 
{
    printf ("could not open file\n");
    return 1; // or exit(1);
}
while ( ( fscanf(handle, " (%f;%f)", &x, &y) ) == 2)
{
    xCoordinate[n] = x;
    yCoordinate[n] = y;
    n++;
    if ( n >= MAXSIZE)
    {
        break;
    }
}

fclose ( handle);

Answer 2

Someone answered this question and then deleted it. Luckily, I saved his code. The best part - it works:

    float xCoordinate [MAXSIZE] = {0.0};
    float yCoordinate [MAXSIZE] = {0.0};

    float x;
    float y;
    FILE *handle;
    int n = 0;

    if ( ( handle = fopen ("points.txt", "r")) == NULL)
    {
        printf ("could not open file\n");
        return 1; // or exit(1);
    }
    while ( ( fscanf(handle, " (%f;%f)", &x, &y) ) == 2)
    {
        xCoordinate[n] = x;
        yCoordinate[n] = y;
        n++;
        if ( n >= MAXSIZE)
        {
            break;
        }
    }

    fclose ( handle);

处理.txt输入为笛卡尔坐标

2 个答案: