c - fscanf 在应该返回 1 的时候始终返回 0

Question

我有一个函数，它接受文件流并将存储在该文件中的整数读取到一维矩阵中。我遇到的问题是我的 fscanf 始终返回 0，而不是我期望的 1。我知道文件开头的格式正确且符合预期，但我不明白为什么它不会读取第一行。我做错了什么？

/* FUNCTION: readToMatrix
    DESCRIPTION:
        This takes an input stream and reads the file (as described in the header documentation),
        filling the array with the integers contained in the input file stream.
    INPUTS:
        file stream, int *array, matrix width
    OUTPUTS:
        Writes to array
    RETURN:
        Returns 0 on success, nonzero on an unexpected failure.
*/

int readToMatrix( FILE *input, int *array, size_t matWidth )
{
    int x,y;
    long num;

    for ( y = 0; y < matWidth; ++y)
    {
        for ( x = 0; x < matWidth-1; ++x )
        {
            // if fscanf doesn't read 1 number or if EOF then return
            if ( fscanf(input, "%ld,", &num) != 1 || feof(input) ) return -1;
            array[x + y*matWidth] = num;
        }
        if ( fscanf(input, "%ld ", &num) != 1 || feof(input) ) return -1;
        array[x + y*matWidth] = num;
    }   
    return 0;
}

注意:这是输入文件开头的一个简短片段。

12177,12690,12499,12985,13005,12574,12882,12896,13026,14539,13704,13539,15182,14361,14539,15333,14615,15231,

Answer 1

您的循环中存在一些小问题。修复这些，就可以正常运行了:

#include<stdio.h>
int readToMatrix( FILE *input, int *array, size_t matWidth , size_t matHeight)
{
    int x,y;
    long num;
    for ( y = 0; y < matHeight; y++)
    {
        for ( x = 0; x < matWidth; x++ )
        {
            // if fscanf doesn't read 1 number or if EOF then return
            if ( fscanf(input, "%ld,", &num) != 1 || feof(input) ) return -1;    
            array[x + y*matWidth] = num;
        }    
    }       
    return 0;
}
int main()
{
    FILE *fd;
    int matWidth = 5 ;
    int matHeight = 5;
    int array[18]; 
    int i;
    fd=fopen("matrix.txt","r");
    if(fd == NULL)
    {
        printf("open failed!\n");
    }
    else
    {
        readToMatrix( fd, array, matWidth , matHeight);
        fclose(fd);
    }
    for(i=0;i<18;i++)
    {
        printf("%d:%d\n",i,array[i]);
    }
    return 0;
}

这里是matrix.txt:

12177,12690,12499,12985,13005,12574,12882,12896,13026,14539,13704,13539,15182,14361,14539,15333,14615,15231 

输出:0:121771:126902:124993:129854:130055:125746:128827:128968:130269:1453910:1370411:1353912:1518213:1436114:1453915:1533316:1461517:15231