For loop exercises

1. A string contains either the signs +, - or 0. Declare an integer with the initial value of 1. On every + in the string, add 1. On every -, subtract 1. On every zero, make the integer be equal zero. After the last symbol, write the value on the screen.
2. Change the previous program so that the ! symbol calculates the factorial of the current value of the integer and saves it in the integer.
3. Copy every second letter of a string into another string and display on the screen.
4. Copy every second word of a string into another string.