Description
This assignment asks you to use the Safe Math library. An example program (Main.c) using this
library can be found at https://paiza.io/projects/hqKdfhnoRkdSNH2GTpOOSA. This example
includes sample input in the Input tab. You may fork this code (that is, add a copy to your account)
using the menu next to the Run button.
If you are not using Paiza, begin by downloading the safe-math.h file from the repository at
https://github.com/nemequ/portable-snippets/tree/master/safe-math. Then copy-paste the code
shown in Main.c at the Paiza link above into your own Main.c file.
As part of the Safe Math library, you will be using the psnip_safe_char_mul,
psnip_safe_int_mul, and psnip_safe_long_mul functions, which are declared and implemented
in the safe-math.h file.
Below is brief documentation for the library functions you will need to use. This documentation
appears in the project’s readme in GitHub. Note: psnip_safe_bools can be used as regular bools.
psnip_safe_bool psnip_safe_char_mul (char* res, char a, char b)
Attempts to multiply chars a and b, and stores the results in the address res. If the operation
can be completed without overflowing or underflowing, a psnip_safe_bool value is returned
that evaluates to true. Otherwise, a psnip_safe_bool that evaluates to false is returned.
psnip_safe_bool psnip_safe_int_mul (int* res, int a, int b)
Attempts to multiply integers a and b, and stores the results in the address res. If the operation
can be completed without overflowing or underflowing, a psnip_safe_bool value is returned
that evaluates to true. Otherwise, a psnip_safe_bool that evaluates to false is returned.
psnip_safe_bool psnip_safe_long_mul (long* res, long a, long b)
Attempts to multiply longs a and b, and stores the results in the address res. If the operation
can be completed without overflowing or underflowing, a psnip_safe_bool value is returned
that evaluates to true. Otherwise, a psnip_safe_bool that evaluates to false is returned.
Use these functions to implement a program that inputs two strings A and B from stdin, converts
A and B to longs (set to 0 if the conversion fails), multiplies A and B using the smallest single type
T, and outputs the result. The eligible types T are char, int, and long, where char is “smaller” than
int and int is “smaller” than long. The two possible program outputs are of the form:
2
1. “A and B can be successfully multiplied as Ts, producing product C.” (where
T is the smallest single type that is large enough for storing A, B, and C)
2. “A and B cannot be multiplied as longs.”
You will want to use the constants CHAR_MIN, CHAR_MAX, INT_MIN, INT_MAX, LONG_MIN, and
LONG_MAX, which are found in the standard C-header file limits.h. For this assignment, you should
only need the Main.c and safe-math.h files, with your Main.c including only the safe-math.h and
standard-library headers (e.g., stdio.h, limits.h, errno.h, and stdlib.h).
Submit to Canvas your completed Main.c file.
Sample Executions
Input 1:
1
2
Output 1:
1 and 2 can be successfully multiplied as chars, producing product 2.
Input 2:
111
222
Output 2:
111 and 222 can be successfully multiplied as ints, producing product 24642.
Input 3:
111111
222222
Output 3:
111111 and 222222 can be successfully multiplied as longs, producing product
24691308642.
Input 4:
11111111111
22222222222
Output 4:
11111111111 and 22222222222 cannot be multiplied as longs.
Input 5:
Here A is set to 0 because this line can’t be converted to a long.
9
Output 5:
0 and 9 can be successfully multiplied as chars, producing product 0.
