c读写文件-优快云博客

该博客整理了C语言读写文件的API，介绍了fopen以二进制模式打开文件时模式字符串需包含“b”字符，fread从流中读取指定大小和数量的元素到内存块，fwrite将内存块中的元素写入流的当前位置，还给出了相关示例的转载链接。

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整理一波c读写文件的API。

fopen

FILE * fopen ( const char * filename, const char * mode );

In order to open a file as a binary file, a "b"character has to be included in the mode string.

fread

size_t fread ( void * ptr, size_t size, size_t count, FILE * stream );

Reads an array of count elements, each one with a size of size bytes, from the stream and stores them in the block of memory specified by ptr.

fwrite

size_t fwrite ( const void * ptr, size_t size, size_t count, FILE * stream );

Writes an array of count elements, each one with a size of size bytes, from the block of memory pointed by ptr to the current position in the stream.

DEMO

#include<stdio.h>

int main()
{
    FILE *fp = fopen("test.txt", "w");
    if (!fp) {
        printf("Open file failed\n");
        return 1;
    }
    char data[] = "hello world!";
    fwrite(data, 1, sizeof(data), fp);
    fclose(fp);
    
    fp = fopen("test.txt", "r");
    if (!fp) {
        printf("Open file failed\n");
        return 1;
    }
    char buffer[64];
    fread(buffer, 1, sizeof(data), fp);
    fclose(fp);
    
    printf("buffer: %s\n", buffer);
    return 0;
}