"fread" 读取数字时读取了错误的值

Question

假设我有一个文件：

file.in:

3 3

并且我想读取其中用fread写的2个数字，所以我这样写：

#include <stdio.h>

int main() {
    int buffer[3] = {0}; // 3 items bcs it also reads the space between the "3"s
    FILE* f = fopen("file.in", "r");

    fread(buffer, 3, 4, f);

    printf("%d %d", buffer[0], buffer[2]);
}

我认为输出应该是 3 3，但我觉得有点像 17?????? 17??????。但是如果我把 int buffer[3] = {0}; 改成 char buffer[3] = {'[=17=]'}; 它就可以正常工作

任何帮助的尝试表示赞赏

Answer 1

fread()用于从文件中读取字节流。 3 3如果使用ASCII则用3个字节表示0x33 0x20 0x33，所以fread(buffer, 3, 4, f);（读取12个字节）不是用来读这个的

如果要将字节存储在 int 中，则应改用 fgetc()。

#include <stdio.h>

int main() {
    int buffer[3] = {0}; // 3 items bcs it also reads the space between the "3"s
    FILE* f = fopen("file.in", "r");

    for (int i = 0; i < 3; i++) {
        buffer[i] = fgetc(f);
    }

    printf("%c %c", buffer[0], buffer[2]); // use %c instead of %d to print the characters corresponding to the character codes
}

"fread" 读取数字时读取了错误的值

"fread" reads wrong values when it's reading numbers

c

file

fread