370p2l error checking

//errors to check for
//duplicate defined global labels
//stack label defined by an object file
//undefined global symbol
int numFiles = argc - 2;
for(int i = 0; i < numFiles; i++)//loop over each file
{
    //check each global symbol
    for(int j = 0; j < files[i].symbolTableSize; j++)
    {
        SymbolTableEntry globalSymbol = files[i].symbolTable[j];

        //check if stack is defined
        if(strcmp(globalSymbol.label, "Stack") == 0 && globalSymbol.location != 'U')
        {
            printf("Symbol \'Stack\' defined locally\n");
            return 1;
        }

        if(globalSymbol.location != 'U')//check for duplicates
        {
            //loop over the other files
            for(int k = 0; k < numFiles; k++)
            {
                //loop over the global symbol file
                for(int l = 0; l < files[k].symbolTableSize; l++)
                {
                    SymbolTableEntry otherGlobalSymbol = files[k].symbolTable[l];
                    if(otherGlobalSymbol.location != 'U' && !((i == k) && (j == l)) && strcmp(globalSymbol.label, otherGlobalSymbol.label) == 0)
                    {
                        printf("Duplicate Global Symbol: %s\n", otherGlobalSymbol.label);
                        return 1;
                    }
                }
            }
        }

        if(globalSymbol.location == 'U')//check if it's defined anywhere
        {
            int defined = 0;
            //loop over the other files
            for(int k = 0; k < numFiles; k++)
            {
                //loop over the global symbol file
                for(int l = 0; l < files[k].symbolTableSize; l++)
                {
                    SymbolTableEntry otherGlobalSymbol = files[k].symbolTable[l];

                    //is this the definition?
                    if(otherGlobalSymbol.location != 'U' && !((i == k) && (j == l)) && strcmp(globalSymbol.label, otherGlobalSymbol.label) == 0)
                    {
                        defined = 1;
                    }
                }
            }
            if(defined == 0)
            {
                printf("Undefined Global Symbol: %s\n", globalSymbol.label);
                return 1;
            }
        }
    }
}
//finished checking for errors