Question

Write a C program that runs on ocelot for a mini calculator using only the command line options. You must use getopt to parse the command line. The calculator will only do addition, subtraction, multiplication, division, and a power of 2.

Usage: minicalc [-a num] [-d num] [-m num] [-s num] [-x] value

• The variable value is the starting value.

• Value should be validated to be an integer between 1 and 50 inclusive. Error message and usage shown if not.

• For the -m option num should be a positive integer between 1 and 5 inclusive.

• For the -d option num should be a positive integer between 1 and 5 inclusive.

• For the -a option num should be a positive integer between 1 and 500 inclusive.

• For the -s option num should be a positive integer between 1 and 500 inclusive.

• -a adds num to value.

• -d divides value by num.

• -s subtracts num from value.

• -m multiplies value by num.

• -x squares value. (Note: no num is needed.)

• Output should have exactly 2 decimal places no matter what the starting values are.

• If -x is included, it is executed first. If -m or -d is included it would be next. The -a and -s would be executed last.

• There will be at most one of each option, if there are more than one you can use either of the options in the calculation.

• There should be no user input while the program is running. It runs in full from the command line.

Create a simple Makefile to compile your program into an executable called minicalc.

Answer 1

Below is the code for the above problem.

main.c

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

//main method to initalize the program
int main(int argc, char *argv[])
{
int option;
int numAdd,numSub,numMul,numDiv,value; //to store operands
int addFlag=0,subFlag=0,mulFlag=0,divFlag=0,squareFlag=0; //flags for operations
/*using getopt function to readflags*/
while((option = getopt(argc, argv, ":a:d:m:s:x")) != -1)
{
switch(option)
{
//if there is flag -a in command line arguments
case 'a':
numAdd = atoi(optarg); //store oprerand of addition
if(numAdd > 500 || numAdd < 1) //check validity of operand
{
printf("For the -a option num should be a positive integer between 1 and 500 inclusive");
}
else //if valid
{
addFlag = 1; //set addition flag
}
break;
//if there is flag -d in command line arguments
case 'd':
numDiv = atoi(optarg); //store oprerand of division
if(numDiv > 5 || numDiv < 1) //check validity of operand
{
printf("For the -d option num should be a positive integer between 1 and 5 inclusive");
}
else //if valid
{
divFlag = 1; ////set division flag
}
break;
//if there is flag -m in command line arguments
case 'm':
numMul = atoi(optarg); //store oprerand of multiplication
if(numMul > 5 || numMul < 1) //check validity of operand
{
printf("For the -m option num should be a positive integer between 1 and 5 inclusive");
}
else //if valid
{
mulFlag = 1; //set multiplication flag
}
break;
//if there is flag -s in command line arguments
case 's':
numSub = atoi(optarg); //store subtaction operand
if(numSub > 500 || numSub < 1) //check validity of operand
{
printf("For the -s option num should be a positive integer between 1 and 500 inclusive");
}
else //if valid
{
subFlag = 1; //set subtaction flag
}
break;
//if there is flag -x in command line arguments
case 'x':
squareFlag = 1; //set squareFlag
break;
//if no operand is provided for listed flags
case ':':
printf("option needs a value\n");
break;
//if unknown flag is provided
case '?':
printf("unknown option: %c\n", optopt);
break;
}
}
  
//if no value is provided
if(argv[optind] == NULL)
{
printf("value is not provided!");
return -1;
}
//storing value operand
value = atoi(argv[optind]);
  
//check validity
if(value > 50 || value < 1)
{
printf("value should be between 1-50");
return -1;
}
  
//if squareFlag is set, do squaring of value
if(squareFlag)
{
printf("Squaring %d ....\n",value);
value = value *value;
printf("Now value becomes : %d\n\n",value);
}
  
//if division flag is set, do division
if(divFlag)
{
printf("dividing %d by %d ....\n",value,numDiv);
value = value / numDiv;
printf("Now value becomes : %d\n\n",value);
}
  
//if multiplication flag is set, do multiplication
if(mulFlag)
{
printf("Multipying %d by %d ....\n",value,numMul);
value = value * numMul;
printf("Now value becomes : %d\n\n",value);
}
  
//if addition flag is set, do addition
if(addFlag)
{
printf("adding %d with %d ....\n",value,numAdd);
value = value + numAdd;
printf("Now value becomes : %d\n\n",value);
}
  
//if subtaction flag is set, do subtaction
if(subFlag)
{
printf("subtracing %d with %d ....\n",value,numSub);
value = value - numSub;
printf("Now value becomes : %d\n\n",value);
}
  
//printing final answer
printf("final answer = %d\n",value);
return 0;
}

makefile

run: minicalc
./minicalc
minicalc: main.c
gcc main.c -o minicalc

OUTPUT:

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