SOLVE USING C++

Problem 1: Write a program that inputs a positive integer N (where N> 0) from the user. It then computes and prints the sum of all positive integers from 1 to N (both limits included). Use a looping structure. Sample Session: Enter value for N: 4 Sum = 10 Problem 2: Write a program that inputs the outside temperature (T), as a floating-point number, from the user. It then prints the appropriate message as indicated in the following table. Use if-| else if structure. Temperature Range T 40 Message to be Printed on Screen Extremely Cold Very Cold Cold Nice Hot Extremely Hot Problem 3: Write a program that asks the user to enter his/her letter grade (as a character 'A', 'B', 'C', 'D', or "F"). The program then displays a message "You passed the course if the letter grade entered is character 'A', 'B', or C'; otherwise, it displays the message You failed the course. Your program must use a switch-case structure