Member Avatar for DelilahDemented

I'm trying to use a switch statement in my code but I'm having a bit of difficulty. I have an error message I do not understand and do not know how to fix. The message reads, "switch quantity not an integer". I'm new to C++ and would appreciate any help given. Thanks in advance!

*Delilah*

#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

int main()
{
    string ssNum = "";
    int numChars = 0;
    string currentChar = 0;
    int subscript = 0;
 
    cout << "Enter a 9-digit social security number without dashes: ";
    getline(cin, ssNum);
    while (ssNum.length() != 9)
    {
          cout << "Item number length is not valid." << endl;
          cout << "Enter a 9-digit social security number without dashes: ";
          getline(cin, ssNum);
    }
    numChars = static_cast<int>(ssNum.length());
    
while (subscript < numChars)
{
      currentChar = ssNum.substr(subscript, 1);
switch(currentChar)
{
                    case '0':
                    case '1':
                    case '2':
                    case '3':
                    case '4':
                    case '5':
                    case '6':
                    case '7':
                    case '8':
                    case '9':
                    break;
                    default :cout<<"Please enter numeric digits only.\n\n";
 }   
}
   
   ssNum.insert(5, "-");
   ssNum.insert(3, "-");
     
   cout << ssNum << endl;
   
   system("Pause");
   return 0; 
    
}
  • 5 Contributors
  • 4 Replies
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  • 7 Hours Discussion Span
  • Latest Post Latest Post by arkoenig

Dani AI

Generated

Quick diagnosis and a minimal plan of action: the compiler message "switch quantity not an integer" means the expression you handed to switch isn't an integral type. In the original code substr(...) returns a std::string, so switch rejects it. Follow ’s hint — use a char (take the character by indexing the string) or test characters with std::isdigit, and make sure the loop index is advanced (or use a for / range-for so you can't forget the ++).

A simple, robust validation pattern (avoids a long switch) is:

#include <cctype>

for (std::string::size_type i = 0; i < ssNum.size(); ++i) {
    unsigned char uc = static_cast<unsigned char>(ssNum[i]);
    if (!std::isdigit(uc)) {
        std::cout << "Please enter numeric digits only.\n";
        break;
    }
}

Notes on that snippet: cast to unsigned char before calling std::isdigit to avoid undefined behavior on platforms where char is signed. Use std::string::size_type (or size_t) for the index to avoid signed/unsigned mismatches.

If a switch is still desired, it must receive a char or integral value (as pointed out). Also remember the semantics mentioned — char values are compared by their numeric code — and ’s clarification: char is an integer type; code-point encoding is an implementation detail, not a switch mechanism.

Final tips: prefer a for or range-based loop to avoid missing the increment, validate all characters before inserting hyphens, and prefer std::all_of / std::isdigit for concise, readable checks in modern C++.

Recommended Answers

All 4 Replies

Member Avatar for tesuji

>> string currentChar = 0;

should be

char currentChar;


Question: how to finish this loop:

>> while (subscript < numChars) ?

so what about subscript++ ?

Greetings to Cotton State! I've often been to Huntsville :)

-- tesu

Edited by tesuji because: n/a
Member Avatar for nbaztec

The gentlemen above me have done a great job & answered well. I'd just like to add that chars inside switches are in fact converted to their ASCII equivalent ints. :)

Member Avatar for arkoenig

The gentlemen above me have done a great job & answered well. I'd just like to add that chars inside switches are in fact converted to their ASCII equivalent ints. :)

Not quite. A char is just an integer with (usually) severe constraints on its value. Operations that involve chars and other integral types have nothing to do with ASCII or any other encoding.

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