(Phone key pads) The international standard letter/number mapping found on the telephone is shown below: 100 2 abc 3 def 4 ghi 5 ikl 6mno 7pgrs 8 tuv 9wxyz Write a program that prompts the user to enter a letter and displays its correspond- ing number.

(Financials: currency exchange) Write a program that prompts the user to enter the exchange rate from currency in U.S. dollars to Rupees PKR. Prompt the user to enter 0 to convert from U.S. dollars to Rupees PKR and 1 to convert from Rupees PKR and U.S. dollars. Prompt the user to enter the amount in U.S. dollars or Rupees PKR to convert it to Rupees PKR or U.S. dollars, respectively. Use c++ program.

5. (Algebra: solve 2 X 2 linear equations) You can use Cramer's rule to solve the following 2 X 2 system of linear equation: ax + by = e cx + dy = f ● x = ed - bf bc ad y = af - ec ad bc - Write a program that prompts the user to enter a, b, c, d, e, and f and display the result. If ad- bc is 0, report that The equation has no solution. Enter a, b, c, d, e, f: 9.0, 4.0, 3.0, -5.0, -6.0, -21.0 Enter x is -2.0 and y is 3.0 Enter a, b, c, d, e, f: 1.0, 2.0, 2.0, 4.0, 4.0, 5.0 Enter The equation has no solution

(Financial: credit card number validation) Credit card numbers follow certain pat- terns. A credit card number must have between 13 and 16 digits. It must start with: 4 for Visa cards 5 for Master cards 37 for American Express cards 6 for Discover cards In 1954, Hans Luhn of IBM proposed an algorithm for validating credit card numbers. The algorithm is useful to determine whether a card number is entered correctly or whether a credit card is scanned correctly by a scanner. Credit card numbers are generated following this validity check, commonly known as the Luhn check or the Mod 10 check, which can be described as follows (for illustra- tion, consider the card number 4388576018402626): 1. Double every second digit from right to left. If doubling of a digit results in a two-digit number, add up the two digits to get a single-digit number. 4388576018402626 → 2 * 2 = 4 → 2 * 2 = 4 → 4 * 2 = 8 → 1 * 2 = 2 6 * 2 = 12 (1+ 2 = 3) → 5 * 2 = 10 (1+ 0 = 1) → 8 * 2 = 16 (1 + 6 = 7) → 4 * 2 = 8

(Count the letters in a string) Write a function that counts the number of letters in a string using the following header: def countLetters(s) : Write a test program that prompts the user to enter a string and displays the number of letters in the string. the answer should be in python.

(Count positive and negative numbers and compute the average of numbers) Write a program that reads an unspecified number of integers, determines how many positive and negative values have been read, and computes the total and average of the input values (not counting zeros). Your program ends with the input 0. Display the maximum, minimum, and average as a floating-point number. Here is a sample run:Enter an integer, the input ends if it is 0: 1 2 -1 3 0The number of positives is 3The number of negatives is 1The maximum is 3.0The minimum is -1.0The average is 1.25

6. (Geometry: area of a pentagon) The area of a pentagon can be computed using the following formula (s is the length of a side): Area 5x s² 4 X tan TT 5 Write a program that prompts the user to enter the side of a pentagon and displays the area. Here is a sample run: Enter the side: 5.5 Enter The area of the pentagon is 53.04444136781625

(Integers Added Together) Create a program that employs the for statement to sum a succession of integers in a single line. Assume that the first integer read defines the number of values that must be entered before the next one may be read. Your software should only read one value per input statement in order to avoid memory leaks. A typical input sequence may be 5 100 200 300 400 500 (or something like). where the number 5 signifies that the items after it are to be added together.

Please review the image below. Produce the program in C++. Upload screenshots of Code and Output, as well as the source code. 6