错误C:\Users\yiersan\Desktop\collect2.exe [Error] ld returned 1 exit status

#include<iostream>
#include<cstdlib>
#include<string>
#include<sys/time.h>
namespace std{
void sayhello(){
    std::cout<<"in sayhello()\n";
}
}
using namespace std;
int main(){
    sayhello();
    string error="error !! then return -1";
    int k=rand()%100;
    //srand(time(0));
    int i=rand()%2146+1;
    cerr.operator<<(i);
    for(int j=0;j<k;j++){
        if(i+100>=2147)
        cout<<error<<endl;
        else
        {
            i++;
            
        }
    }
    clog.operator<<(i) ;
    return 0;
}