C语言--文件 *** 作

C语言--文件 *** 作

文章目录

• C语言--文件 *** 作
• 一、*包括：*``fgetc`` ``fputc`` ``fgets`` ``fputs`` ``fopen`` ``fclose`` 的使用
• 运行结果：
• 二、``fread`` 和 ``fwrite``

C语言–文件 *** 作 一、包括：fgetc fputc fgets fputs fopen fclose 的使用

#include 
fputc1()
{
	FILE* pf = fopen("test1.txt", "w");         ' //以写的模式打开一个文件test1.txt  '
	if (pf == NULL)
	{
		perror("fopen");
		exit(1);
	}
	fputc('x', pf);						' //写入字符'x' 'w' 'p'     
	fputc('w', pf);
	fputc('p', pf);
	fclose(pf);							' //关闭文件   '  
	pf = NULL;
}
fgetc1()
{
	FILE* pf = fopen("test1.txt", "r");
	if (pf == NULL)
	{
		perror("fopen");
		exit(1);
	}
	for (int i = 0; i < 3; i++)
	{
		printf("%cn", fgetc(pf));
	}
	fclose(pf);
	pf = NULL;
}
fputs1()
{
	FILE* pf = fopen("test1.txt", "w");
	if (pf == NULL)
	{
		perror("fopen");
		exit(1);
	}
	fputs("xwp is handsome", pf);
	fputs("Yeah!n", pf);
	fputs("I agree you", pf);
	fclose(pf);
	pf = NULL;
}
fgets1()
{
	FILE* pf = fopen("test1.txt", "r");
	if (pf == NULL)
	{
		perror("fopen");
		exit(1);
	}
	char arr1[40] = { 0 };
	fgets(arr1, 40, pf);
	puts(arr1);
	char arr2[20] = { 0 };
	fgets(arr2, 20, pf);
	puts(arr2);
	fclose(pf);
	pf = NULL;
}
int main()
{
	fputc1();
	fgetc1();
	fputs1();
	fgets1();
	return 0;
}

运行结果：

创建了一个test1.txt文件，内容如下：

二、fread 和 fwrite

fseek ftell rewind的使用示例

//fread fwrite fseek ftell rewind
//fwrite 
struct S
{
	char arr[10];
	int a;
	float f;
};
void fwrite1()
{
	struct S sarr[] = { {"xpwhs", 25, 25.05f},
						{"yzmhc", 25, 25.5f},
						{"I agree", 66, 66.66} };
	FILE* pf = fopen("test.dat", "wb");
	if (pf == NULL)
	{
		perror("fopen");
		fputs("FILE ERROR", stderr);
	}
	fwrite(sarr, sizeof(struct S), 3, pf);
	fclose(pf);
	pf = NULL;
}
//fread
void fread1()
{
	FILE* pf = fopen("test.dat", "rb");
	if (pf == NULL)
	{
		perror("fopen");
		fputs("FILE ERROR", stderr);
		exit(1);
	}
	' //计算文件的大小，对应的开辟内存空间  '
	fseek(pf, 0, SEEK_END);
	long lsize = ftell(pf);
	rewind(pf);
	struct S* buffer = (struct S*)malloc(lsize);
	if (buffer == NULL) { fputs("malloc error", stderr); exit(2); }
	fread(buffer, sizeof(struct S), 3, pf);
	fclose(pf);
	pf = NULL;
	'  //显示buffer内容   '
	for (int i = 0; i < 3; i++)
	{
		printf("%s %d %fn", buffer[i].arr, buffer[i].a, buffer[i].f);
	}
	free(buffer);
	buffer = NULL;
}
int main()
{
	fwrite1();
	fread1();
	return 0;
}

写入的test.dat如下所示：

显示的内容：