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6.8 Compare Characters
Chapter 6 ■ Characters
Characters can be compared using the relational operators ==, !=, <, <=, > and >=. We’ve
compared the char variable ch with a blank using ch == ' ' and ch != ' '.
Let us now write a program to read a line of data and print the ‘largest’ character, that is, the
character with the highest code. For instance, if the line consisted of English words, the letter that
comes latest in the alphabet would be printed. (Recall, though, that lowercase letters have higher
codes than uppercase letters so that, for instance, 'g' is greater than 'T'.)
‘Finding the largest character’ involves the following steps:
• Choose a variable to hold the largest value; we choose bigChar.
• Initialize bigChar to a very small value. The value chosen should be such
that no matter what character is read, its value would be greater than this
initial value. For characters, we normally use '\0'—the null character, the
‘character’ with a code of 0.
• As each character (ch, say) is read, it is compared with bigChar; if ch is
greater than bigChar, then we have a ‘larger’ character and bigChar is set to
this new character.
• When all the characters have been read and checked, bigChar will contain
the largest one.
These ideas are expressed in Program P6.8.
Program P6.8
//read a line of data and find the 'largest' character
#include <stdio.h>
int main() {
char ch, bigChar = '\0';
printf("Type some data and press 'Enter' \n");
while ((ch = getchar()) != '\n')
if (ch > bigChar) bigChar = ch; //is this character bigger?
}
printf("\nThe largest character is %c \n", bigChar);
The following is a sample run; u is printed since its code is the highest of all the characters typed.
Type some data and press 'Enter'
Where The Mind Is Without Fear
The largest character is u
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