Question

我需要获得此输出：

但相反，我得到了这个：

我是C编程新手。所以，我不知道为什么我输错了。这就是我做的。我应该将每个列存储在不同的变量中。因为在将它们存储在不同的变量后，我需要为它们进行数学计算。

#include<stdio.h>
#include<stdlib.h>
#include <string.h>
#include <math.h>
#include <stdint.h>
#include <stdbool.h>

int main (int argc, char *argv[]) {

    FILE *fptr;

    fptr = fopen(argv[1], "r");

    if (fptr != NULL) {
        size_t i;
        int SIZE = 1000;
        int*x[500]; 
        int*y[500]; 
        int*z[500]; 
        int ch=0;
        int l;
        int n=0;
        char line[100];

        while ((ch=fgetc (fptr))!= EOF) {
            if (ch=='\n')
            n++;
        }

        printf("Number of lines = %d\n", n);

        for (l=0; l<n;++l) {
            while(fgets(line,sizeof line,fptr)) { 
                printf("%s",line);
                sscanf(line,"%d %d %d",&x[l],&y[l],&z[l]);
            } 
        }

        for (i=0; i<l;++i) {
            printf("%d %d %d\n",x[i],y[i],z[i]);
        }

        fclose(fptr);
        return 0 ;
    }

Answer 1

我至少看到了两个问题。

fptr在计算行数时已经到了文件末尾。因此，rewind() fptr计算行数后，因为它已经上升到文件末尾。所以在第一次循环后添加rewind(fptr)。
您不需要x, y, z作为指针数组，而只需要一个数组。所以将它们改为
```
int x[500]; 
int y[500]; 
int z[500];
```

Answer 2

好的，我们先用评论对此进行排序：

#include<stdio.h>
// i dont think the following includes are nessesary for the given code
//#include<stdlib.h>
//#include <string.h>
//#include <math.h>
//#include <stdint.h>
//#include <stdbool.h>

int main (int argc, char *argv[]) {

    FILE *fptr;
    // i wonder a little about what youre opening here with argv[1]
    // since arrays start counting at 0
    // for testing and more understandability maybe just put the file
    // where your code is and deliver its filename as a string?
    fptr = fopen(argv[1], "r");

    if (fptr != NULL) {
        // whats that? you use it as a counting variable, make it int
        // not size_t
        size_t i;
        // its not good practive to have a variable in capitals
        // if you wanna make it a constant, you should define it
        // at the beginning of the code, right after your includes
        int SIZE = 1000;
        // dont use pointers (these -> "*") here! Maybe you mix up
        // dynamic array declaration (which requires using malloc() and
        // no brackets like "int * dynArray;") with static arrays
        // correct usage would be: int x[500]; thats it
        int*x[500]; 
        int*y[500]; 
        int*z[500]; 
        int ch=0;
        // just a hint for more readability: use "j" instead of "l" but
        // thats really up to you :D
        int l;
        int n=0;
        char line[100];

        // here you loop through your file char by char and just count
        // the lines. Why dont pick the chars on the fly and actually
        // write something into your defined arrays x, y, z ?
        // some additional conditions (if) may do the trick
        while ((ch=fgetc (fptr))!= EOF) {
            if (ch=='\n')
            n++;
        }

        printf("Number of lines = %d\n", n);

        // sizeof is a function, so youre missing the parentheses
        // and above that, you already know the size of your line array
        // because its statically defined to hold 100 * sizeof(char)
        // my suggestion: trash this entire loop and rethink the previous
        for (l=0; l<n;++l) {
            while(fgets(line,sizeof line,fptr)) { 
                printf("%s",line);
                sscanf(line,"%d %d %d",&x[l],&y[l],&z[l]);
            } 
        }

        // cool loop. but there was no input to x, y, z except the first
        // element of your line array, which seems to hold just a 0
        // so everythings correct here, the mistake occured before
        for (i=0; i<l;++i) {
            printf("%d %d %d\n",x[i],y[i],z[i]);
        }

        //nice, thats important :)
        fclose(fptr);
        return 0 ;
    }

我希望它可以帮助你理清事物并指导一个更清晰的问题，这个问题可能会自己回答？：d

从c程序中的文件读取行输出错误的输出

2 个答案: