Following is my solution for basicmath problem.

I am still not satisfied with the efficiency of the code but happy that I tried by myself and could do it.

#include<iostream>

#include <stdlib.h>

using namespace std;

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

{

if (argc < 4){

cout<<"<Number> <+-x/> <Number> <Enter>" << endl;

}

else if(argc == 4)

{

int i = 1;

int j = 0;

int count=0;

int firstArg;

int thirdArg;

while(argv[i])

{

if(i != 2)//check if first and third commandline arguements have digits only.

{

while(!isdigit(argv[i][j]) && argv[i][j])

{

count++;//to count characters except digits

j++;//count digits

}

}

i++;//loop for frist and second arguements

}

if(count > 0)//if there are other characters other than digits

{

cout<<"<Number> <+-x/> <Number> <Enter>" << endl;

}

else if(*argv[2] == '+')

{

firstArg = atof(argv[1]);

thirdArg = atof(argv[3]);

cout<< firstArg + thirdArg << endl;

}

else if(*argv[2] == '-')

{

firstArg = atof(argv[1]);

thirdArg = atof(argv[3]);

cout<< firstArg - thirdArg << endl;

}

else if(*argv[2] == 'x')

{

firstArg = atof(argv[1]);

thirdArg = atof(argv[3]);

cout<< firstArg * thirdArg << endl;

}

else if(*argv[2] == '/')

{

firstArg = atof(argv[1]);

thirdArg = atof(argv[3]);

cout<< firstArg / thirdArg << endl;

}

}

}

////steps

///*

//-first determine how many arguments are there?

//if there are less than four args then print right format

//if there are 4 args in total than

//check first and third arguments contain numbers only

//if not print right format

//if yes then check second argument contain one of these(+-x/)

//if not print right format

//if yes then convert first and third arguements to integer

//at last do the calculations