floats 'n integers

[MPrestonf12]

int gains;

for(i=1;i<=j;i++){
		cout<<i<< " ";
	gains = (amountY*interestR)/100.0f;
	amountY = amountY + gains;
	cout <<amountY << endl;
	}

The problem here is that amountY and interestR have to be integers, becasue they were formmated as a character and I had to format them to a integer. But gains has to be a float. Is there a way to convert things to work correctly, that is mixing a float and integer? Can I convert char to float? Thanks