Using C++ Write a command line calculator in C++. The calculator supports the fo

Question

Using C++

Write a command line calculator in C++. The calculator supports the following mathmatical operations:

• Multiplication m

• Divison d

• Subtraction s

• Addition a

• Percentage p

The following example show cases how this calculator can be used

The calculator should also support a commandline option --history, which displays the list of all previous calculations. Check out the following example:

$ ccalc p 2 10 Ans: 20
$ calc --history History:
p 2 10
20
a23
5
m 2 40
80

By necessity you’ll have to use a file to save/load the history. For the purposes of this exercise, lets assume that the history is stored in file ccalc-history.txt sitting in the local directory.

Explanation / Answer

#include <iostream.h>
#include <string.h>
#include <stdlib.h>
#include <conio.h>
#include <stdio.h>
#include <ctype.h>
//using namespace std;
FILE *fp;
char str[10];
void add(int a,int b){
   int r;
   r=a+b;
   cout<<r;
   sprintf(str,"a %d %d %d ",a,b,r);
   fwrite(&str,sizeof(str),1,fp);
}
void sub(int a,int b){
   int r;
   r=a-b;
   cout<<r;
   sprintf(str,"s %d %d %d ",a,b,r);
   fwrite(&str,sizeof(str),1,fp);

}
void mul(int a,int b){
   int r;
   r=a*b;
   cout<<r;
   sprintf(str,"m %d %d %d ",a,b,r);
   fwrite(&str,sizeof(str),1,fp);
}
void divi(int a,int b){
   int r;
   r=a/b;
   cout<<r;
   sprintf(str,"d %d %d %d ",a,b,r);
   fwrite(&str,sizeof(str),1,fp);
}

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

   char op;
   char *test;
   int val1,val2;
   clrscr();
   test=argv[1];
   if(*(test+1)==0) {
       op=*argv[1];
       val1=atoi(argv[2]);
       val2=atoi(argv[3]);
       fp=fopen("ccalchistory.txt","a+");
       cout<<val1<<" "<<val2<<endl;
       switch(op)
       {
           case 'a':
           case 'A': add(val1,val2); break;
           case 's':
           case 'S': sub(val1,val2); break;
           case 'm':
           case 'M': mul(val1,val2); break;
           case 'd':
           case 'D': divi(val1,val2); break;
           default: cout<<"invalid input";

       }
   }
   else if(!strcmp("--history",argv[1])){
       if(fp=fopen("ccalchistory.txt","r")){
           char ch1;
           ch1=getc(fp);
           while(ch1!=EOF){
               cout<<ch1;
               ch1=getc(fp);

           }
       }
       else{
           printf("no history");
       }
   }
   else{
       cout<<"invalid input";
   }
   fclose(fp);
   getch();
}

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