Preliminary Material

We are not far enough into C to do more interesting things $($pointers and such are yet to come but are coming soon$),$ yet an important topic can be addressed now: command line arguments.

What is a command line argument? You have already used them in completing programs $0$ and $1.$ In program $0,$ when you typed $$gcc helloworld.c$$ to compile your source file, both $$gcc$$ and $$helloworld$.$c$$ were command line arguments. Likewise for program $1,$ in $$gcc p$0.$c$$ both the $$gcc$$ and $$p$0.$c$$ were command line arguments. Command line arguments are the textual material in the command that initiates execution of the program in the system.

In both C and C$++,$ there are actually two arguments to the $$main$()$ function that are generally left out if the program does not examine command line arguments. Here is how they are declared when they are used.

int main$($int argc, char$*$ argv$[])$

The meaning of these arguments is as follows.

int argc the number of command line arguments passed by the OS to the program.

char$*$ argv$[]$ argv is an array of char pointers, each to a command line argument.

$($By convention, these names are always used for C and C$++$ main$()$s formal parameters.$)$

Remember, array indices in C start with $0.$ This is $$zero$-$based$$ indexing. The C string pointed to by argv$[0]$ is either the name of the program invoked or the full path, including name, of the program invoked. Thus, argc will always have a value of at least $1.$

Assignment

Write a program named clt$.$c that accepts four command line arguments in addition to the argv$[0]$ program name$/$path and produces an output to the console as follows.

Your program will accept four command line arguments $($indices $1$ to $4)$ in the following order and with the following meanings, then output to console a table of temperatures in degrees Fahrenheit, Celsius and Kelvin.

A single ASCII character that must be an $$c$,$C$,$f$,$F$,$k$$ or $$K$.$

A $$c$$ or $$C$$ indicates conversion from Celsius to Fahrenheit and Kelvin,

an $$f$$ or $$F$$ from Fahrenheit to Celsius and Kelvin, and

a $$k$$ or $$K$$ from Kelvin to the other two.

An integer value indicating the starting temperature in the scale specified.

An integer value indicating the temperature not to be exceeded.

A floating$-$point value indicating the step between values $(2$ and $3)$ in the scale specified.

Print a header line as follows.

Celsius Fahrenheit Kelvin

Starting with the temperature indicated by argv$[2],$ in the scale specified by argv$[1],$ calculate the equivalent temperatures in the other two scale, then print the values to the stdout $($console output$).$ The overall format should be as follows.

Celsius Fahrenheit Kelvin

####$.$## ####$.$## ####$.$##

Values are to be right$-$justified with two decimal digits.

Increment the temperature in the scale from argv$[1]$ by the value from argv$[4]$ and repeat the process until the upper bound in argv$[3]$ is reached. Print the values if the argv$[3]$ value is matched, but not if exceeded.

Your submission must compile without errors using the gcc compiler on csx and the program must run correctly on csx$.$

Submission to csx will use the following command on csx$.$

$$handin cs$2433-$rlchurc program$2$ clt$.$c$$

Please note that the Linux operating system and both C and C$++$ are case sensitive$.$

To assist in matching alignments to those above, the following indicates columns.

$0123456789012345678901234567890123456789$

Celsius Fahrenheit Kelvin

####$.$## ####$.$## ####$.$##