Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 8 ■ Arrays
Suppose a country’s data are read into the variables country, capital and CAPITAL,
respectively. (Remember that, in C, capital is a different variable from CAPITAL.) When the user
types an answer (answer, say), it must be compared with capital. If we use a straightforward
comparison like
if (strcmp(answer, capital) == 0) ...
to check if answer is the same as capital, then answers such as "Portof Spain,""port of
spain,"" Port ofSpain," and "st georges" would all be considered wrong. If we want these
answers to be correct (and we probably should) we must convert all user answers to a common
format before comparing.
We take the view that as long as all the letters are there, in the correct order, regardless of
case, the answer is considered correct. When the user types an answer, we ignore spaces and
punctuation and convert the letters only to uppercase. This is then compared with CAPITAL. For
example, the answers above would be converted to "PORTOFSPAIN" and "STGEORGES" and would
elicit a "Correct!" response.
In the palindrome program (P8.5), we wrote a function lettersOnlyLower that kept the
letters only from a string and converted them to lowercase. Here, we want the same function but
we convert to uppercase instead. We name the function lettersOnlyUpper. The code is identical
to lettersOnlyLower except that tolower is replaced by toupper. Our test for correctness now
becomes this:
lettersOnlyUpper(answer, ANSWER);
if (strcmp(ANSWER, CAPITAL) == 0) printf("Correct!\n");
All the details are captured in Program P8.7.
Program P8.7
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#define MaxLength 50
int main() {
void getString(FILE *, char[]);
void askOneQuestion(char[], char[], char[]);
char EndOfData[] = "*", country[MaxLength+1] ;
char capital[MaxLength+1], CAPITAL[MaxLength+1];
FILE * in = fopen("quizdata.txt", "r");
if (in == NULL){
printf("Cannot find file\n");
exit(1);
}
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