Question

C++ language only. Thank you

C++ language (cout <). NO atoi function. And please pay attention to the rules at the bottom. Extra good rating to whoever can help me with this. TIA. In certain programming situations, such as getting information from web forms, via text boxes, the data coming in may need to be numerical (we want to perform arithmetic on it), but it is stored in the form of a list of characters (the numerical value stored is based upon the table above). Therefore, as the programmer, we must convert the character to an integer digit or the string containing digits as characters to its decimal equivalent. YOUR JOB: For this project, you will simulate this conversion. Your program will ask the user to enter a 4 digit numerical value. As the programmer, you will input the value as a string. You will devise an algorithm to convert the string of characters (string of digits) to a single integer, stored in a single integer value. At the end of this algorithm, you will print the addition (using the operator) of the input string to itself, and the addition of the converted integer to itself. For example, if the user were to input 9275, the outputs would be 18550 and 92759275 !!!'Your program should generate appropriate error messages if the user ent less than 4 digits, (2) more than 4 digits, or (3) any non-numeric digits. !!!CONSTANTS should be used in place of literals where appropriate !!!!!Meaningful variable and constant names should match the intent or the purpose of the data item-use words, not abbreviations. Try to avoid loops if possible.

Answer 1

Please find the code below with detailed inline comments.

CODE

=========================

#include <iostream>
#include <cstring>
#define SIZE 4 // CONSTANT to represent the size of the number`

using namespace std;

int main() {
string number_str;
cout << "Enter a 4-digit number: ";
getline(cin, number_str);
int length = number_str.length(); // stores the length of the input string
  
// the length of the input string is less than 4
if(length < SIZE) {
cout << "Error.... the number has less than 4 digits!!" << endl;
}
// the length of the input string is greater than 4
else if(length > SIZE) {
cout << "Error.... the number has more than 4 digits!!" << endl;
}
  
int number = 0; // represent the numerical value of the input string
  
// loop through all the characters of the input string
for(int i=0; i<number_str.length(); i++) {
int digit = number_str[i] - '0';  
// the character is not a digit, print error message
if(digit < 0 || digit > 9) {
cout << "Error.... the given string is not a valid number!!" << endl;
return 0;
}
  
// update the number value
number = number * 10 + digit;
}
  
  
// print the output
cout << "The output is: " << endl;
cout << number + number << ", " << number_str + number_str;
return 0;
}

OUTPUT

=========================

Enter a 4-digit number: 9275 The output is: 18550, 92759275

Enter a 4-digit number: 12r4 Error.... the given string is not a valid number! I