Chapter 4 : Character Strings and Formatted Input/Output

2.Assuming that each of the following examples is part of a complete program, what will each one print?

a. 

printf("He sold the painting for $%2.2f.
", 2.345e2);

b.

printf("%c%c%c
", 'H', 105, '41');

c.

#define Q "His Hamlet was funny without being vulgar." 
printf("%s
has %d characters.
", Q, strlen(Q));

d.

printf("Is %2.2e the same as %2.2f?
", 1201.0, 1201.0);

a. He sold the painting for $234.50.
b. Hi!
c. "His Hamlet was funny without being vulgar."
has 44 characters.
d. Is 1.20e+03 the same as 1201.00?

3. In Question 2c, what changes could you make so that string Q is printed out enclosed in double quotation marks?

#define Q ""His Hamlet was funny without being vulgar.""

4. It's the find error time!

define B booboo 
define X 10 
main(int)
{
int age; 
char name;
printf("Please enter your first name."); 
scanf("%s", name);
printf("All right, %c, what's your age?
", name); 
scanf("%f", age);
xp = age + X;
printf("That's a %s! You must be at least %d.
", B, xp); 
rerun 0;
}

Here is a corrected version:

#include <stdio.h> /* don't forget this */

#define B "booboo" /* add #, quotes */
#define X 10       /* add #	*/

int main(void) /* instead of main(int) */
{
    int age;
    int xp;    /* declare all variables */
    char name[40];    /* make into an array	*/

    printf("Please enter your first name.
"); /* 
 for readability */
    scanf("%s", name);
    printf("All right, %s, what's your age?
", name); /* %s for string */
    scanf("%d", &age);    /* %d, not %f, &age, not age */
    xp = age + X;
    printf("That's a %s! You must be at least %d.
", B, xp);
    return 0;    /* not rerun	*/
}

5. Suppose a program starts as follows:

#define BOOK "War and Peace" 
int main(void)
{
float cost =12.99; 
float percent = 80.0;

Construct a printf() statement that uses BOOK, cost, and percent to print the following:

This copy of "War and Peace" sells for $12.99.

That is 80% of list.

printf("This copy of "%s" sell for $%.2f
That is %.0f%% of list", BOOK, cost,
           percent); //Note the conversion specifier for 80% here!!!

6. What conversion specification would you use to print each of the following?

a. A decimal integer with a field width equal to the number of digits

b. A hexadecimal integer in the form 8A in a field width of 4

c. A floating-point number in the form 232.346 with a field width of 10

d. A floating-point number in the form 2.33e+002 with a field width of 12

e. A string left-justified in a field of width 30

a. %d

b. %4X

c. %10.3f

d. %12.2e

e. %-30s

7. Which conversion specification would you use to print each of the following?

a. An unsigned long integer in a field width of 15

b. A hexadecimal integer in the form 0x8a in a field width of 4

c. A floating-point number in the form 2.33E+02 that is left-justified in a field width of 12

d. A floating-point number in the form +232.346 in a field width of 10

e. The first eight characters of a string in a field eight characters wide

a. %15lu

b. %#4x

c. %-12.2E

d. %+10.3f

e. %8.8s

8. What conversion specification would you use to print each of the following?

a. A decimal integer having a minimum of four digits in a field width of 6

b. An octal integer in a field whose width will be given in the argument list

c. A character in a field width of 2

d. A floating-point number in the form +3.13 in a field width equal to the number of characters in the number

e. The first five characters in a string left-justified in a field of width 7

a. %6.4d

b. %*o

c. %2c

d. %+0.2f

e. %-7.5s

9. For each of the following input lines, provide a scanf() statement to read it. Also declare any variables or arrays used in the statement.

a. 101

b. 22.32 8.34E−09

float 

c. linguini

d. catch 22

e. catch 22 (but skip over catch)

a. 

int a;
scanf("%d", &a);

b.

float a, b;
scanf("%f %f", &a, &b);

c.

char charArray[20];
scanf("%s", charArray);

d.

char charArray;
int num;
scanf("%s %d", charArray, num);

e. 

char charArray[20];
int num;
scanf("%*s %d", &num); // Note that here we use an * to skip reading charArray

10. What's whitespace?

Whitespace consists of spaces, tabs, and newlines. C uses whitespace to separate tokens from one another; scanf() uses whitespace to separate consecutive input items from each other.

11. What’s wrong with the following statement and how can you fix it?

printf("The double type is %z bytes..
", sizeof (double));

The z in %z is a modifier, not a specifier, so it requires a specifier for it to modify. You could use %zd to print the result in base 10 or use a different specifier to print using a different base, for example, %zx for hexadecimal.