C++ If Else Statement variable problems

I need help in my c++ codes. The Problem here is when I run the program. Is there a problem with my variables or the if else statement I am using.

So example when i put 101 it will state "Please Input A Valid Grade". If I input none of the numbers in the if statement, it will go to "else" and displays "Failed". What I need for the program to happen is when I put "inc" it will display "Incomplete".. Please help. Here is the sample code:

#include <iostream>
#include <string>
using namespace std;
int main()
{
float grade;
char inc;
cout <<"Enter Your Grade: ";
cin >> grade;
if (grade>100 || grade<0)
{       
    cout <<"Please Input A Valid Grade";
}
else if(grade>=94)
{
    cout <<"Your Equivalent Grade is 1.00";
    cout <<"\nExcellent!";
}
else if(grade>=88.5)
{
    cout <<"Your Equivalent Grade is 1.25";
    cout <<"\nSuperior!";
}
else if(grade>=83)
{
    cout <<"Your Equivalent Grade is 1.5";
    cout <<"\nMeritorius!";
}
else if(grade>=77.5)
{
    cout <<"Your Equivalent Grade is 1.75";
    cout <<"\nVery Good!";
}
else if(grade>=72)
{
    cout <<"Your Equivalent Grade is 2.00";
    cout <<"\nGood!";
}
else if(grade>=68.5)
{
    cout <<"Your Equivalent Grade is 2.25";
    cout <<"\nVery Satisfactory!";
}
else if(grade>=61)
{
    cout <<"Your Equivalent Grade is 2.50";
    cout <<"\nSatisfactory!";
}
else if(grade>=55.5)
{
    cout <<"Your Equivalent Grade is 2.75";
    cout <<"\nFair!";
}
else if(grade>=50)
{
    cout <<"Your Equivalent Grade is 3.00";
    cout <<"\nPassing!";
}
else if(grade>50)
{
    cout <<"Your Equivalent Grade is 5.00";
    cout <<"\nFailed!";
}
    else
{
    cout <<"Your Equivalent Grade is 5.00";
    cout <<"\nFailed!";
}
if(grade=inc)
{
    cout <<"Your Equivalent Grade is 4.00\n";
    cout <<"YOU ARE INCOMPLETE";
}

}