使用fscanf将文本文档的内容扫描到C语言的数组中

Question

I need to scan the contents of a text document, namely;

77, 66, 80, 81
40,  5, 35, -1
51, 58, 62, 34
 0, -1, 21, 18
61, 69, 58, 49
81, 82, 90, 76
44, 51, 60, -1
64, 63, 60, 66
-1, 38, 41, 50
69, 80, 72, 75

into an array, with each number in its own block, and then read each block to identify what the contents are. I feel like I have the processing part complete, but I can't work out how to allocate a number to a block in the array. Here is what I have so far;

int main()
{
    FILE * marks;
    marks = fopen("marks.txt", "r");
    int marksArray[4][10], x, y, greaterThan70 = 0, between60and69 = 0, between50and59 = 0, between40and49 = 0, lessThan39 = 0, notSubmitted = 0;
    //Scanning in the contents
    while ((fscanf(marks, "%d", &marksArray[x][y])) != EOF)
    {
        x++;
        y++;
    }
    //Processing the array
    for(x = 0; x < 4; x++)
    {
        for(y = 0; y < 10; y++)
        {
            if(marksArray[x][y] == -1)
            {
                notSubmitted++;
            }
            else if(marksArray[x][y] >= 0 && marksArray[x][y] <= 39)
            {
                lessThan39++;
            }
            else if(marksArray[x][y] >= 40 && marksArray[x][y] <= 49)
            {
                between40and49++;
            }
            else if(marksArray[x][y] >= 50 && marksArray[x][y] <= 59)
            {
                between50and59++;
            }
            else if(marksArray[x][y] >= 60 && marksArray[x][y] <= 69)
            {
                between60and69++;
            }
            else
            {
                greaterThan70++;
            }
            break;
        }
    }
    printf("The number of marks greater than 70 was %d", greaterThan70);
    printf("The number of marks between than 60 and 69 was %d", between60and69);
    printf("The number of marks between than 50 and 59 was %d", between50and59);
    printf("The number of marks between than 40 and 49 was %d", between40and49);
    printf("The number of marks less than 39 was %d", lessThan39);
    printf("The number of coursework submissions not handed in was %d", notSubmitted);
}

Answer 1

First, are you really sure that you can't do this in C++ ( ifstream )( getline ) ?

Secondly, if you must do it in C, then you should look into the file and count the number of lines and the number of comma on each line. To get the total number of line in the file

You can then iterate again the file, line by line and count the number of comma ( if there is not always 4 numbers on each line like in your question ).

Answer 2

(fscanf(marks, "%d", &marksArray[x][y])

Chokes on the first comma. You'll want something more like:

(fscanf(marks, "%d, ", &marksArray[x][y])

The comma and white space (which also eats new lines) are important. Except that your last character doesn't end with a comma, so that won't quite work.

Yeah, and this:

while ((fscanf(marks, "%d", &marksArray[x][y])) != EOF)
{
    x++;
    y++;
}

If it worked, it would walk through the array in this pattern:

X000
0X00
00X0
000X

What you want is something more like:

#include <stdio.h>

int main()
{
FILE * marks;
marks = fopen("in.txt", "r");
int marksArray[4][10], x, y, greaterThan70 = 0, between60and69 = 0, between50and59 = 0, between40and49 = 0, lessThan39 = 0, notSubmitted = 0;
//Scanning in the contents
//No need for EOF if you know the size ahead of time
for(y=0; y<10; y++)
{
  for(x=0; x<3; x++)
  {
    fscanf(marks, "%d, ", &marksArray[x][y]);
  }      
  //To deal with the annoying lack of comma at the end of the line
  //Be wary of EoL variance, the difference between \n and \r\n, bloody windows...
  fscanf(marks, "%d\n", &marksArray[x][y]);
}

//Processing the array
for(x = 0; x < 4; x++)
{
    for(y = 0; y < 10; y++)
    {
        if(marksArray[x][y] == -1)
        {
            notSubmitted++;
        }
        else if(marksArray[x][y] >= 0 && marksArray[x][y] <= 39)
        {
            lessThan39++;
        }
        else if(marksArray[x][y] >= 40 && marksArray[x][y] <= 49)
        {
            between40and49++;
        }
        else if(marksArray[x][y] >= 50 && marksArray[x][y] <= 59)
        {
            between50and59++;
        }
        else if(marksArray[x][y] >= 60 && marksArray[x][y] <= 69)
        {
            between60and69++;
        }
        else
        {
            greaterThan70++;
        }
        break;
    }
}
printf("The number of marks greater than 70 was %d\n", greaterThan70);
printf("The number of marks between than 60 and 69 was %d\n", between60and69);
printf("The number of marks between than 50 and 59 was %d\n", between50and59);
printf("The number of marks between than 40 and 49 was %d\n", between40and49);
printf("The number of marks less than 39 was %d\n", lessThan39);
printf("The number of coursework submissions not handed in was %d\n", notSubmitted);
}

And don't listen to that guy C is awesome and the right language for every problem. Ever.