【IO】C语言文件操作接口

c语言提供的cstdio头文件中的IO操作

文件打开函数(验证mode)

std::FILE* fopen( const char* filename, const char* mode );
//mode:"r";"w";"a";"r+";"w+";"a+";"b"

文件关闭函数

int fclose( std::FILE* stream );

Parameters
stream	-	the file stream to close

Return value
​0​ on success, EOF otherwise

文件写入函数

std::size_t fwrite( const void* buffer, std::size_t size, std::size_t count, std::FILE* stream );

Parameters
buffer	-	pointer to the first object object in the array to be written
size	-	size of each object in bytes
count	-	the number of the objects to be written
stream	-	output file stream to write to

Return value
Number of objects written successfully, which may be less than count if an error occurred.
If size or count is zero, fwrite returns zero and performs no other action.

文件读取函数

std::size_t fread( void* buffer, std::size_t size, std::size_t count, std::FILE* stream );

Parameters
buffer	-	pointer to the first object in the array to be read
size	-	size of each object in bytes
count	-	the number of the objects to be read
stream	-	input file stream to read from

Return value
Number of objects read successfully, which may be less than count if an error or end-of-file condition occurs.
If size or count is zero, fread returns zero and performs no other action.

写入文件示例

#include <cstdio>

    std::FILE *fp;
    fp = std::fopen(filePath, "w");//  fp = std::fopen(filePath, "r");
    if (fp == NULL) {
        //打开文件失败
    } else {
        //打开文件成功，写入数据
    	std::fwrite(&var, sizeof(var), varNumber, fp);//写入文件
    	std::fclose(fp);//文件关闭
    }