checking an int in c++
// CPP program to check if a given string
// is a valid integer
#include <iostream>
using namespace std;
// Returns true if s is a number else false
bool isNumber(string s)
{
for (int i = 0; i < s.length(); i++)
if (isdigit(s[i]) == false)
return false;
return true;
}
// Driver code
int main()
{
// Saving the input in a string
string str = "6790";
// Function returns 1 if all elements
// are in range '0-9'
if (isNumber(str))
cout << "Integer";
// Function returns 0 if the input is
// not an integer
else
cout << "String";
}