非初始化变量，但我试着接受变量的输入?

I'm trying to set up an input that takes in a price and quantity of an item and it keeps giving me the uninitialized variable error for both of them so I give them a variable of 0 under the main and yet it won't print out the input and just shows their value to be 0?I'm trying to set up an input that takes in a p