Write a program to get strings and to substitute character from string1 to string2 (equv to UNIX command tr)
for example:
string1: "abc"
string2: "def"
the occurrence of 'a' will be replaced by 'd' , 'b' will be replaced by 'e' , 'c' will be replaced by 'f' AND for less complexity assume the string1 and string2 are of same size.