Program Instructions: Write a program that performs simple math expressions on command line arguments.

$1.$ The program should take exactly $3$ arguments and check the number of arguments

$2.$ Convert args $1$ and $3$ to numbers with atoi$().$ Note that atoi returns $0$ for errors; you can ignore this for now.

$3.$ Check arg $2$ for valid math operations $+-/$ x with if or switch statements

$4.$ Perform the correct math operation and print the results according to the sample output on the next page.

Format the printed output EXACTLY as in the sample output below $($including spacing and line skips$).$ If the number of arguments is wrong or the math symbol isn$$t recognized, print the word Usage and then some sensible usage instructions $($however$,$ for grading I'll only be checking that the first $5$ characters are Usage $).$

Note that in the samples below, the $ represents the bash prompt and is printed automatically by bash. Don$$t print dollar signs from your C program. The first line shows what you type, the second and third lines are the output if done correctly.

Sample of correct usage and resulting output:

$ a$.$out $50*-10$

$ $50*-10=-500$

$

Sample of incorrect usage $($no spaces between arguments$)$ which causes usage instructions to be printed

$ a$.$out $5+3$

$ Usage $...$

$