Class Average Calculator(Help!)

[Amaiha]

My assignment wants me to input scores via line command, but I'm not sure how I'm supposed to do that.

#include<iostream>
#include<cmath>
#include<string>

using namespace std;


float labs(){
float lgrade, labg;
cout<< "Enter the total points you have for labs: ";
cin>> lgrade;
return(labg = lgrade * .10);
}

float quiz(){
float qgrade, quizg;
cout<<"Enter the total points you have for quizzes: ";
cin>> qgrade;
return(quizg = qgrade * .10);
}

float assign(){
float agrade, assigng;
cout<<"Enter the total points you have for assignments: ";
cin>> agrade;
return(assigng = agrade * .40);
}

float exam(){
float egrade, examg;
cout<<"Enter the total points you have for exams: ";
cin>> egrade;
return(examg = egrade * .25);
}

float final(){
float fgrade, finalg;
cout<<"Enter the total points you have for the final: ";
cin>> fgrade;
return(finalg = fgrade * .15);
}



int main(){

int labg, quizg, assigng, examg, finalg;

labg = labs();
quizg = quiz();
assigng = assign();
examg = exam();
finalg = final();

int grade;

grade = labg + quizg + assigng + examg + finalg;
cout<<grade<<endl;

return 0;

}

[rcast]

http://www.cplusplus.com/articles/DEN36Up4/

parameters placed in main( * here * ) argv and argc

[Amaiha]

What should I do after that?

[Amaiha]

Help!

[AbstractionAnon]

int main (int argc, const char * argv[])
{  int labg, quizg, assigng, examg, finalg;
    if (argc != 6)
    { cout << "Wrong number of command line arguments" << endl;
       return 0;
    }
    // argv[0] is the program name, so we start from argv[1]
    labg = atoi(argv[1]);  // convert first parameter to an integer
    //  etc for the other arguments
    //  calculate grade ... 
}

[Amaiha]

since labg = atoi(argv[1]);
it only lets the user input lab grades as the first.. i.e.
./a.out -labg 98 -quizg 100 etc...
How do I make it so it doesn't matter which order the user inputs it?

[AbstractionAnon]

Then you're going to have to parse the command line.

Keep in mind that spaces in the command line delimit the arguments.

-labg 98

is two arguments.

[Amaiha]

what does parse command line mean?

[AbstractionAnon]

To parse something means to break it apart into individual tokens and then process the individual tokens.

The C runtime has already taken the command line and broken it apart into individual tokens for you. It's given you a list of those tokens starting at argv[1].

Your job is to look at each of those tokens and determine which keyword (e.g. "-labg") it matches. If it matches a keyword, move on to the next token and convert it to a number, then assign it to the appropriate integer (e.g. variable labg).

  int i = 1;    // index to first token
  while (i <= argc) 
  {  if (strcmp(argv[i],"-labg") == 0)
        labg = atoi(argv[i+1]);
      // repeat for other keywords
      i += 2;
   }

The above code is just a general outline. It doesn't check that argv[i+1] is a number or even if it exists. It also doesn't deal with the command line being empty or if a keyword doesn't match.

[Amaiha]

Why do we do i += 2 at the end?

[Amaiha]

Also, do I put the other keywords inside the while loop as well?

[AbstractionAnon]

Why do we do i += 2 at the end?

Because the arguments are in pairs.

do I put the other keywords inside the while loop as well?

Yes. That's what the "repeat for other keywords" meant.

[Amaiha]

i have some problem just going into the while loop.

35  int check_arguments(int argc, char *argv[]){
 34    int i=1, l, q, a, e, f;
 35    cout<<"boop"<<endl;
 36    while(i<=argc){
 37       if( strcmp(argv[i], "-l") == 0){
 38          l = atoi(argv[i+1]);
 39          cout<<"beep"<<endl;
 40       }
 41       else if (strcmp(argv[i], "-q") == 0){
 42          q = atoi(argv[i+1]);
 43       }
 44       else if (strcmp(argv[i], "-a") == 0){
 45          a = atoi(argv[i+1]);
 46       }
 47       else if (strcmp(argv[i], "-e") == 0){
 48          e = atoi(argv[i+1]);
 49       }
 50       else if (strcmp(argv[i], "-f") == 0){
 51          f = atoi(argv[i+1]);
 52       }
 53    }
 54    i +=2;
 55
 56    set_scores(l);
 57 }
 58
63 }
 66.int main (int argc, char *argv[]){
 67    check_arguments(argc, argv);

[Amaiha]

cout << boop and beep are just there for me to check if it went into the loop.

[AbstractionAnon]

i += 2; must be inside the while loop.