New programs add

telephone_number_validator.cpp

@@ -0,0 +1,28 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+int main()
+{
+    string number;
+    cout<<"Enter Mobile Number: ";
+    cin>>number;
+
+    bool flag = 0;
+    int i = 0;
+    while(number[i])
+    {
+        if(number[i] < 48 || number[i] > 57) //check if all the characters are numeric if not we set flag = 1
+            {
+                flag = 1;
+                break;
+            }
+        i++;
+    }
+
+    if(!flag && number.length() == 10) //check if flag is not set and length is 10.
+        cout<<"Phone Number Valid";
+    else
+        cout<<"Phone Number NOT Valid";
+
+    return 0;
+}