Taking Input through a string in c++

Question

In C, suppose I need to take input from a string

 int num,cost;
 char *name[10];
 printf("Enter your  inputs [quantity item_of_name at cost]");
 scanf("%d%*c%s%*c%*s%*c%d",&num,name[0],&cost);

 printf("quantity of item: %d",num);
 printf("the cost of item is: %d",cost);
 printf("the name of item is: %d",name[0]);

INPUT

1 book at 12

OUTPUT

Quantity of item is: 1

The cost of item is: 12

The name of item is: book

Now I want to do the same thing in C++. And I have no idea how to approach. gets() returns the whole string.Is there any specific function that I am missing out on? Please help.

Your question is a bit confused because your C code doesn't take input from a string but from standard input. What are you really trying to do? Also the C functions you are using will also work in C++. — john
– john, Commented Oct 12, 2012 at 11:01
His C code is broken anyway: he passes an uninitialized pointer as the third argument to scanf. And even if it were initialized: users can easily crash the program with a long enough name. In C, you never use "%s" in a scanf without specifying the maximum length. — James Kanze
– James Kanze, Commented Oct 12, 2012 at 11:10
All I am trying is making use of format specifiers to store the appropriate input (in the string )into corresponding variables. Now I have never seen usage of C functions (or what we use in C) in C++. (I am not saying you can't..just I am still a beginner).Basically I am trying to transpose the problem from C to C++. — Piyp791
– Piyp791, Commented Oct 12, 2012 at 11:10
@Peps The C++ way of doing input is given by sehe, but the C way works too. — john
– john, Commented Oct 12, 2012 at 11:20

sehe · Accepted Answer · 2012-10-12 10:58:31Z

6

int num,cost;
std::string name;
std::cout << "Enter your  inputs [quantity item_of_name at cost]: ";
if (std::cin >> num >> name >> cost)
{ } else 
{ /* error */ }

You will want to add errorhandling

answered Oct 12, 2012 at 10:58

sehe

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Comments

tsionyx · Accepted Answer · 2012-10-12 10:59:05Z

0

In C++ you should rather use cin, cout and string from standard library.

answered Oct 12, 2012 at 10:59

tsionyx

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Comments

tomahh · Accepted Answer · 2012-10-12 11:01:23Z

0

In c++, std::stream provides the read and write communication with the user through the >> operator.

Your code translates to

int num,cost;
std::string name;

std::cout << "Enter your  inputs [quantity item_of_name at cost]" << std::flush;
std::cin >> num >> name;
std::cin >> at; // skip the at word
std::cin >> cost;

std::cout << "quantity of item: " << num << std::endl;
std::cout << "the cost of item is: " << cost << std::endl;
std::cout << "the name of item is: " << name << std::endl;

answered Oct 12, 2012 at 11:01

tomahh

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Comments

M4rc · Accepted Answer · 2012-10-12 11:08:21Z

0

You could use iostream's cin.

int num,cost;
 char *name[10];
 std::cout <<"Enter your quantity"<<std::endl;
 std::cin>> num;
 std::cout<<" Enter the cost"<<std::endl;
 std::cin>>cost;
 std::cout<<"Enter the name"<<std::endl;

 std::cout<<"The quantity of the item is: "<<num<<" costing: "<<cost<<" for "<<name[0]<<std::endl;

and then of course you could also use std::string instead of char*.

Or streamline the cin's as cin >> num >> cost >> name;

Also, as Griwes noted, you will want to perform error checking on your results.

edited Oct 12, 2012 at 11:08

answered Oct 12, 2012 at 10:59

M4rc

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4 Comments

M4rc Over a year ago

Yeah, but I would imagine that goes without saying.

Griwes Over a year ago

OP looks like newbie (generally, he looks like someone educated that C++ is just "C with classes" and taught some C basics), so I think it's important remark here.

M4rc Over a year ago

My assumption is that because he was using (well knew how to) a array of char pointers, that he knew error handling, but in my sedation didn't stop to consider this could be a homework question and that code just have been provided. Good catch, and noted as well.

Sebastian Mach Over a year ago

Your code yields the same undefined behavior as the questioner's. Better replace could with should and tell him/her about the error.

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