linux1% g++ input1.cpp

linux1% cat data2
Hello     World     
   good
3.14159
linux1% ./a.out < data2
str1 = 'Hello'
str1[1] = 'e'
str2 = 'World'
str3 = 'good'
str4 = '3.14159'
f = 3.14159
linux1%