Chapter 21, Problem 21.14E

Program Plan Intro

Program Plan:

• Include header files.
• Make two character arrays “ a” and “ b ”.
• Get the message in “ a ”.
• Use “strlen()” function to get length of the entered message in variable “ len ”.
• Run the for loop for value 1 to len
• Convert every character to lowercase using “tolower()” function.
• If character is not space then check that if we add 13 to the current character i.e. a[i], the resultant character is less than or greater than character ‘z’.
• If not going beyond ‘z’ then make b[i]=a[i]+13.
else make b[i]=a[i]-13.

• If current character a[i] is space make b[i]=a[i], which means putting space in array b.
• End of for loop
• Put ‘\0’ − null character in the end of array b.
• Display the array b as encrypted message.