学习笔记7(二进制文件读写,C的预处理)

一. 二进制文件读写

读的函数 fread()

fread的API

写的函数 fwrite()

fwrite的API

int main(){

    char *read_path = "E:\\C_NDK_data\\LogViewPro.exe";
    char *write_path = "E:\\C_NDK_data\\LogViewPro_write.exe";

    //读二进制文件
    FILE * read_fp = fopen(read_path, "rb");//rb读二进制的
    //写二进制文件
    FILE * write_fp = fopen(write_path,"wb");

    char buff[50];
    int len = 0;
    while ((len = fread(buff,sizeof(char),50,read_fp)) != 0){
        fwrite(buff,sizeof(char),len,write_fp);
    }
    fclose(read_fp);
    fclose(write_fp);
    system("pause");
    return 0;
}

二. 获取文件大小

fseek() 设置流的文件位置为给定的偏移量:

fseek的API

ftell() 返回给定流 stream 的当前文件位置

ftell的API

int main(){

    char *read_path = "E:\\C_NDK_data\\LogViewPro.exe";
    FILE * read_fp = fopen(read_path, "r");
    if (read_fp == NULL){
        return 0;
    }
    fseek(read_fp,0,SEEK_END);//从文件的末尾做0个偏移
    long fileSize = ftell(read_fp);
    printf("%ld \n", fileSize);

    fclose(read_fp);
    system("pause");
    return 0;
}