小编joh*_*262的帖子

我写了一个小程序来解密一个OTP加密的文件.这很好用.

但是我意识到在"Solution.jpg"上调用fopen时我忘了保存返回的文件指针.如您所见,我正在写入文件指针f.我想知道为什么这个代码工作.

#include <stdio.h>

#define FILE_SIZE 4202

int main () {
    unsigned char key[FILE_SIZE], otpCipher[FILE_SIZE];

    FILE *f = fopen("otpkey.bin", "r");
    fread(key, sizeof(char), FILE_SIZE, f);
    fclose(f);

    f = fopen("otpcipher.bin", "r");
    fread(otpCipher, sizeof(char), FILE_SIZE, f);
    fclose(f);

    fopen("Solution.jpg", "w");

    for (int j = 0; j < FILE_SIZE; ++j) {
        otpCipher[j] = otpCipher[j] ^ key[j];
        fputc(otpCipher[j], f);
    }

    fclose(f);

    return 0;
}