bool findVal(vector <int>::iterator beg,vector <int>::iterator end,int m)
{
    bool iflag;
    while (beg!=end)
    {
        if (*beg==m)
            iflag=true;
        else
            iflag=false;
        beg++;//少了这一句
    }
    return iflag;
}

#include <iostream> 
#include <vector>
 
int main()
{
bool findVal(vector <int>::iterator beg,vector <int>::iterator end,int m);
vector <int> ivec(10);
for(int i=0;i!=10;++i)
     ivec[i]=i;
for(int i=0;i!=10;++i)
     cout <<ivec[i] <<" ";
     cout <<endl;
bool flag;
vector <int>::iterator iter1=ivec.begin();
vector <int>::iterator iter2=ivec.end();
flag=findVal(iter1,iter2,7);
if(!flag)
     cout <<"Donot find the value." <<endl;
     cout <<"Find the value." <<endl;
return 0;
} 
bool findVal(vector <int>::iterator beg,vector <int>::iterator end,int m) 
{
     bool iflag;
     while(beg!=end)
     {
          if(*beg==m)
               iflag=true;
          else
               iflag=false;
     }
return iflag;
}