C/C++中scanf、sscanf、fscanf函数用法

#include <stdio.h>
#include <stdlib.h>

int main(int atgc, int *argv[])
{
	int a;
	char buf[100] = {0};
	FILE *file = NULL;

	printf("请输入一个数字：");
	scanf("%d", &a);
	printf("a = %d\n", a);

	sscanf("123456", "%2d", &a);
	sscanf("abcdef", "%4s", buf); // 取指定长度的字符串
	printf("a = %d\nbuf:%s\n", a, buf);
	
	//取到指定字符为止的字符串
	sscanf("123456 abcdedf", "%[^ ]", buf); //取遇到空格为止字符串
	printf("取到指定字符为止的字符串:%s\n", buf);
	sscanf("123456abcdedfBCDEF", "%[^A-Z]", buf); //取遇到大写字母为止的字符串
	printf("取到指定字符为止的字符串:%s\n", buf);

	// 取仅包含指定字符集的字符串
	sscanf("123456abcdedfBCDEF", "%[1-9a-z]", buf); //取仅包含1到9和小写字母的字符串
	printf("取仅包含指定字符集的字符串:%s\n", buf);

	//获取两个指定字符之间的字符串
	sscanf("iios/12DDWDFF@122", "%*[^/]/%[^@]", buf);
	printf("取两个指定字符之间的字符串:%s\n", buf);

	//给定一个字符串"hello, world"，仅保留"world"
	sscanf("hello, world", "%*s%s", buf); // %*s表示第一个匹配到的%s被过滤掉
	printf("%s\n", buf);

	//从文件中读取
	file = fopen("hello.txt", "r");
	if(NULL!= file)
	{
		fscanf(file, "%s", buf);
		printf("从文件中读取：%s\n", buf);
	}
	fclose(file);

	return 0;
}