Previous: 4.7 Summary
Up: 4 Processing Character Data
Next: 4.9 Problems
Previous Page: 4.7 Summary
Next Page: 4.9 Problems

4.8 Exercises

1. What is the value of each of the following expressions:

   ch = 'd';
   
   (a)   ((ch >= 'a') && (ch <= 'z'))
   (b)   ((ch > 'A') && (ch < 'Z'))
   (c)   ((ch >= 'A') && (ch <= 'Z'))
   (d)   ch = ch -'a' + 'A';
   (e)   ch = ch - 'A' + 'a';

2. What will be the output of the following:

   char ch;
        int d;
   
        ch = 'd';
        d = 65;
        printf("ch = %c, value = %d\n", ch, ch);
        printf("d = %d, d = %c\n", d, d);

3. Write the header file category.h discussed in section 4.1.2. Write the macros IS_UPPER(), IS_DIGIT(), IS_PUNCT(), IS_SPACE(), IS_CONTROL().
4. Write a code fragment to test:
   • if a character is printable but not alphabetic
   • if a character is alphabetic but not above 'M' or 'm'
   • if a character is printable but not a digit
5. Write separate loops to print out the ASCII characters and their values in the ranges:

   'a' to 'z',
        'A' to 'Z',
        '0' to '9'.

6. Are these the same: 'a' and "a"? What is the difference between them?

7. What will be the output of the source code:

   #define SQ(x) ((x) * (x))
        #define CUBE(x)  ((x) * (x) * (x))
        #define DIGITP(c) ((c) >= '0' && (c) <= '9')
   
        char c = '3';
   
        if (DIGITP(c))
             printf("%d\n", CUBE(c - '0'));
        else
             printf("%d\n", SQ(c - '0'));

8. Find the errors in the following code that was written to read characters until end of file.

   char c;
   
        while (c = getchar())
             putchar(c);

9. What will be the output of the following program?

   #include <stdio.h>
   main()
   {    int n, sum;
        char ch;
   
        ch = 'Y';
        sum = 0;
        scanf("%d", &n);
        while (ch != 'N') {
             sum = sum + n;
             printf("More numbers? (Y/N) ");
             scanf("%c", &ch);
             scanf("%d", &n);
        }
   }

10. What happens if scanf() is in a loop to read integers and a letter is typed?

11. What happens if scanf() reads an integer and then attempts to read a character?

12. Use a switch statement to test if a digit symbol is an even digit symbol.

13. Write a single loop that reads and prints all integers as long as they are between 1 and 100 with the following restrictions: If an input integer is divisible by 7 terminate the loop with a break statement; if an input integer is divisible by 6, do not print it but continue the loop with a continue statement.