invalid operands to binary expression ('ostream' (aka 'basic_ostream<char>') and 'void')
<p>I have homework for Data Structure in college with LinkedLists ,</p>

<p>did the code but the compiler "eclips" shows me an error called 
Description Resource    Path    Location    Type</p>

<p>invalid operands to binary expression ('ostream' (aka 'basic_ostream') and 'void')    LinkedLists.cpp /LinkedLists/src    line 156    C/C++ Problem</p>

<p>and this is the code , so what's this issue ? and how can i fix it?</p>

<p>Thanks ^^</p>

<pre><code>struct node {
    int StudentNumber;
    string name;
    node *link,*data;

    };

node *head,*newNode,*last;
string name;
int StudentNumber;

node* insert (){
            char a='n';
            cout&lt;&lt;"hello to linked lists insertion"&lt;&lt;endl;

            cout&lt;&lt;endl&lt;&lt;"please write your name : ";
            cin&gt;&gt;name;
            cout&lt;&lt;"please put the student number : ";
            cin&gt;&gt;StudentNumber;
            head=NULL;

            while(a!='n'||a!='N'){

                newNode = new node ;
                newNode-&gt;StudentNumber=StudentNumber;
                newNode-&gt;name=name;
                newNode-&gt;link=NULL;

                if (head==NULL)
                {
                    head=newNode;
                    last=newNode;

                }else {

                    last-&gt;link=newNode;
                    last=newNode;

                }//end else


                cout&lt;&lt;"please write your name : ";
                cin&gt;&gt;name;
                cout&lt;&lt;endl&lt;&lt;"please put the student number : ";
                cin&gt;&gt;StudentNumber;
                cout&lt;&lt;"Do you want to insert new nodes ? y for yes , n for no ";
                cin&gt;&gt;a;


            }//end while

            return head;
    }//end insert function


// adding nodes function

void add() {
    int j;
    cout&lt;&lt;"please choose your option for adding new node : 1 for add at the beginning , 2 for add at the end ";
    cin&gt;&gt;j;
    if (head!=NULL)
        {
    switch (j)
{
    // adding at the beginning
case 1 :
        newNode=new node;
        newNode-&gt;link=head;
        head=newNode;
        cout&lt;&lt;"please insert your node data : ";
        cout&lt;&lt;"Student Name : "&lt;&lt;newNode-&gt;data&lt;&lt;endl&lt;&lt;"and student number is : "&lt;&lt;newNode-&gt;StudentNumber;

    break;
    // at the end
case 2:
    newNode= head;
    while (newNode-&gt;link!=NULL)
    {
        newNode = newNode-&gt;link;

    }// end of while
    last= newNode;
    newNode = new node ;
    newNode-&gt;link=NULL;
    last-&gt;link=newNode;
    cout&lt;&lt;"please insert your node data : ";
    cout&lt;&lt;"Student Name : "&lt;&lt;newNode-&gt;data&lt;&lt;endl&lt;&lt;"and student number is : "&lt;&lt;newNode-&gt;StudentNumber;
    break; // end of case adding at the end


}
}else {cout&lt;&lt;"The list is empty";}

}// ending of the adding nodes function


// delete node function

void deletion () {
    int s;
    cout&lt;&lt;"please choose your option for deleting nodes : 1 for delete the first , 2 for delete the last node ";
            cin&gt;&gt;s;
switch (s) {
// delete the first node
case 1 :
    newNode = head;
    last=head-&gt;link;
    head=last;
    delete newNode;
    break;

    //delete the last node
case 2:
    newNode=head;
    last=head;
    while (newNode-&gt;link!=NULL)
    {
        last=newNode;
        newNode=newNode-&gt;link;
    }
    last-&gt;link=NULL;
    delete newNode;
    break;


}//end of the switch


}// end of delete nodes function




int main() {
    int m;
    cout&lt;&lt;"Welcome to LinkedLists Example"&lt;&lt;endl;
    cout&lt;&lt;"enter your choice number , 1 for inserting nodes to the list , 2 for adding nodes , 3 for deleting nodes ";
    cin&gt;&gt;m;
    switch(m) {
    case 1:
        cout&lt;&lt;insert();
        break;
    case 2:
        cout&lt;&lt;add();
        break;
    case 3:
        cout&lt;&lt;deletion();
        break;


    }

return 0;
</code></pre>

<p>}</p>