Biegral Blog

      fseek函数用来设置文件指针stream的位置，原型为：

int fseek(FILE *stream, long offset, int fromwhere);

      下面先对fseek有一个初步的认识，以后具体用到时，如果不清楚，可以查阅相关（网络）资料.

#include<iostream>
using namespace std;

int main()
{
	int offset;
	int fromWhere; // 0表示文件开头

	FILE *fp = fopen("myData.txt", "w");
	fprintf(fp, "123456");
	cout << ftell(fp) << endl;

	offset = 0;
	fromWhere = 0;
	fseek(fp, offset, fromWhere);
	cout << ftell(fp) << endl;

	offset = 1;
	fromWhere = 0;
	fseek(fp, offset, fromWhere);
	cout << ftell(fp) << endl;

	fclose(fp);

	cout << "*********************" << endl;

	int a[10];
	memset(a, 0, sizeof(a));

	fp = fopen("yourData", "wb");
	fwrite(a, sizeof(a), 1, fp);
	cout << ftell(fp) << endl;

	offset = 5;
	fromWhere = 0;
	fseek(fp, offset, fromWhere);
	cout << ftell(fp) << endl;

	fclose(fp);

	return 0;
}

      结果为：

6
0
1
*********************
40
5