c - 从文本文件中读取数字并将其用作输入

Question

我有这样的文字:

0 0 0 0 0 1
0 0 0 0 1 1
0 0 0 1 0 1
0 0 0 1 1 1

我想读取每行的前 5 个数字，然后将它们用作函数的输入。

我是 c 语言新手，只完成了这段代码，如果真的有什么作用的话，它并没有做太多事情。

    int v,o;
    FILE *mydata;

    if ((mydata = fopen("testinputs.txt", "rt"))==NULL)
    {
        printf ("file can't be opened'\n");
        exit(1);}


    fclose(mydata);

我该如何完成它？

谢谢。

Answer 1

好吧，假设您的文件名为“input.txt”，那么这就是您需要做的:

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

#define LINE_LEN 100
int main ( void )
{
    char line[LINE_LEN];
    int sum, i, read_cnt, numbers[5];//sum and i are there for my example usage
    FILE *in = fopen("input.txt", "r");//open file
    if (in == NULL)
    {
        fprintf(stderr, "File could not be opened\n");
        exit( EXIT_FAILURE);
    }
    while((fgets(line, LINE_LEN, in)) != NULL)
    {//read the line
        //scan 5 numbers, sscanf returns the number of values it managed to extract
        read_cnt = sscanf(
            line,
            "%d %d %d %d %d",
            &numbers[0],
            &numbers[1],
            &numbers[2],
            &numbers[3],
            &numbers[4]
        );
        //check to see if we got all 5 ints
        if (read_cnt != 5)
            printf("Warning: only read %d numbers\n", read_cnt);//whoops
        //just an example, let's add them all up
        for (sum= i=0;i<read_cnt;++i)
            sum += numbers[i];
        printf("Sum of numbers was: %d\n", sum);
    }
    return EXIT_SUCCESS;
}

使用此 input.txt 文件:

1 2 3 4 5 
2 2 2 2 2
1 23 2 3 4
12 23

这为我们提供了以下输出:

Sum of numbers was: 15
Sum of numbers was: 10
Sum of numbers was: 33
Warning: only read 2 numbers
Sum of numbers was: 35

这应该足以让您开始使用