Create Number_String_check.cpp

Checks input is string or number.

Number_String_check.cpp

@@ -0,0 +1,31 @@
+// 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";
+}