查閱了百度，借鑑了許多大牛的程式碼，自己的整理如下：

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;

int main()
{
    //例1：從<sip:[email protected]>中提取tom
    const char* url = "<sip:[email protected]>";
    char uri[10] = {0};
    sscanf(url, "%*[^:]:%[^@]", uri);
    cout << uri << endl;

    //例2：從iios/
 
[email protected]中提取 12DDWDFF
    const char* s = "iios/[email protected]";
    char buf[20];
    sscanf(s, "%*[^/]/%[^@]", buf);
    cout << buf << endl;

    int k;
    sscanf( "AAA123BBB456" , "%*[^0-9]%i" , &k) ;
    printf("%d\n",k);
    return 0;
}