1.Write a program that appends one file at the end of another. 2. Write a program that reads a file containing integers and appends at its end the sum of all the integers. 3. Write a program that...

2. Write a program that reads a file containing integers and appends at its end the sum of all

the integers. 3. Write a program that prompts the user for two files, one containing a line of text known as source file and other, an empty file known as target file and then copies the contents of source file into target file. Modify the program so that a specified character is deleted from the source file as it is copied to the target file.