Cannot call another function within class?

[SimbaSpirit]

This one is probably a basic oversight...

First, the code:

//in format.cpp:

void format::setIntLargestValue (int intInput){
        intLargestValue = intInput;
    }
    int format::getIntLargestValue(){
        return(intLargestValue);
    }
    void numberChecker(string strInput){
        if (strInput.length() > format::getIntLargestValue()){
            format.setIntLargestValue(strInput.length());
        }
    }

setIntLargestValue is just a local proxy. But this is one example of about 10 similar implementations of what I'm trying to do.

When I compile I get "error: cannot call member function `int format::getIntLargestValue()' without object"
Now I understand what it's trying to tell me, but is there not a way to call the a function of this class without having to declare an object?
I'm trying to avoid writing this inside the class:

format clFormat;
...
clFormat.setIntLargestValue(intInput);
...

Any thoughts??