I keep getting errors. Programming in C

Program 4. Write a program that combines programs 1 through 3 into one vending machine user interface program. First welcome the user and display the drink options, prompt the user for their drink selection, enter their selection, and record the amount due for a small (program 3). Next, display the size options, prompt the user for the size, enter their size selection, and record the price multiplier (program 2). Based on the size entered, your program should adjust the amount due. Next, display the amount due, prompt the user for their payment, enter their payment, and determine the amount of change to return (program 1). Note: the flow chart for this program does not have to include the entire flow charts for programs 1 through 3. Rather, it can put a brief description of each of the smaller programs in a compute box and show the flow of control for between each smaller program. Any additional computations or control should also be included In program 4 you should remove any unnecessary print statements used in programs 1 through 3 that do not display useful information to the user