C Tutorial - Answers
====================================================================
#include
int main()
{
printf("John Q. Doe\n");
return 0;
}
/* Result of execution
John Q. Doe
*/
====================================================================
#include
int main()
{
printf("John Q. Doe\n");
printf("1234 Main Street\n");
printf("(505) 555-1212\n");
return 0;
}
/* Result of execution
John Q. Doe
1234 Main Street
(505) 555-1212
*/
====================================================================
#include
int main()
{
int index;
/* index = 13; */
printf("The value of the index is %d\n", index);
index = 27;
printf("The value of the index is %d\n", index);
index = 10;
printf("The value of the index is %d\n", index);
return 0;
}
====================================================================
#include
int main()
{
int index;
index = 13;
printf("The value of the index is %d\n", index);
index = 27;
printf("The value of the index is %d\n", index);
index = 10;
printf("The value of the index is %d\n", index);
printf("Index is %d\n it still is %d\n it is %d",
index, index, index);
return 0;
}
====================================================================
#include
int main()
{
int index;
for(index = 0 ; index < 10 ; index = index + 1)
printf("John Q. Doe\n");
return 0;
}
/* Result of execution
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
*/
====================================================================
#include
int main()
{
int index;
index = 0;
while (index < 10)
{
printf("John Q. Doe\n");
index = index + 1;
}
return 0;
}
/* Result of execution
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
*/
====================================================================
#include
int main()
{
int index;
index = 0;
do
{
printf("John Q. Doe\n");
index = index + 1;
} while (index < 10);
return 0;
}
/* Result of execution
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
*/
====================================================================
#include
int main()
{
int index;
index = 1;
do
{
printf("The count is now %2d",index);
if (index == 3)
printf(" and is equal to three.");
if (index == 7)
printf(" and is equal to seven.");
printf("\n");
index = index + 1;
} while (index < 11);
return 0;
}
/* Result of execution
The count is now 1
The count is now 2
The count is now 3 and is equal to three.
The count is now 4
The count is now 5
The count is now 6
The count is now 7 and is equal to seven.
The count is now 8
The count is now 9
The count is now 10
*/
====================================================================
#include
int main()
{
int index, square;
for(index = 1 ; index < 13 ; index = index + 1)
{
square = index * index;
printf("%5d%5d\n", index, square);
}
return 0;
}
/* Result of execution
1 1
2 4
3 9
4 16
5 25
6 36
7 49
8 64
9 81
10 100
11 121
12 144
*/
====================================================================
#include
int main()
{
int index;
float inversion;
for(index = 1 ; index < 13 ; index = index + 1)
{
inversion = 1.0/index;
printf("%5d%9.5f\n", index, inversion);
}
return 0;
}
/* Result of execution
1 1.00000
2 .50000
3 .33333
4 .25000
5 .20000
6 .16667
7 .14286
8 .12500
9 .11111
10 .10000
11 .09091
12 .08333
*/
====================================================================
#include
int main()
{
int index;
for(index = 1 ; index < 101 ; index = index + 1)
{
if ((index >= 32) && (index <= 39))
printf("%5d\n", index);
}
return 0;
}
/* Result of execution
32
33
34
35
36
37
38
39
*/
====================================================================
/****************************************************************/
/* */
/* This is a temperature conversion program written in */
/* the C programming language. This program generates */
/* and displays a table of farenheit and centigrade */
/* temperatures, and lists the freezing and boiling */
/* of water. */
/* */
/****************************************************************/
#include "stdio.h"
int tempcalc(itn centtemp);
int main()
{
int count; /* a loop control variable */
int farenheit; /* the temperature in farenheit degrees */
int centigrade; /* the temperature in centigrade degrees */
printf("Centigrade to Farenheit temperature table\n\n");
for(count = -2 ; count <= 12 ; count = count + 1)
{
centigrade = 10 * count;
farenheit = tempcalc(centigrade);
printf(" C =%4d F =%4d ", centigrade, farenheit);
if (centigrade == 0)
printf(" Freezing point of water");
if (centigrade == 100)
printf(" Boiling point of water");
printf("\n");
} /* end of for loop */
return 0;
}
int tempcalc(int centtemp)
{
int faren;
faren = 32 + (centtemp * 9)/5;
return (faren);
}
/* Result of execution
Centigrade to Farenheit temperature table
C = -20 F = -4
C = -10 F = 14
C = 0 F = 32 Freezing point of water
C = 10 F = 50
C = 20 F = 68
C = 30 F = 86
C = 40 F = 104
C = 50 F = 122
C = 60 F = 140
C = 70 F = 158
C = 80 F = 176
C = 90 F = 194
C = 100 F = 212 Boiling point of water
C = 110 F = 230
C = 120 F = 248
*/
====================================================================
#include "stdio.h"
void writename();
void writename()
{
printf("John Q. Doe\n");
}
int main()
{
int index;
for(index = 0 ; index < 10 ; index = index + 1)
writename();
return 0;
}
/* Result of execution
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
John Q. Doe
*/
====================================================================
/* Chapter 5 - Program 1 - SUMSQRES.C */
/* Chapter 5 - Programming exercise 3 */
#include
void header(void);
void square(int number);
void ending(void);
int sum; /* This is a global variable */
int main(void)
{
int index;
header(); /* This calls the function named header */
for (index = 1 ; index <= 7 ; index++)
square(index); /* This calls the square function */
ending(); /* This calls the ending function */
return 0;
}
void header(void) /* This is the function named header */
{
sum = 0; /* Initialize the variable "sum" */
printf("This is the header for the square program\n\n");
}
void square(int number) /* This is the square function */
{
int numsq;
numsq = number * number; /* This produces the square */
sum += numsq;
printf("The square of %d is %d\n", number, numsq);
}
void ending(void) /* This is the ending function */
{
printf("\nThe sum of the squares is %d\n", sum);
}
/* Result of execution
This is the header for the square program
The square of 1 is 1
The square of 2 is 4
The square of 3 is 9
The square of 4 is 16
The square of 5 is 25
The square of 6 is 36
The square of 7 is 49
The sum of the squares is 140
*/
====================================================================
#include
#define START 7
#define END -5
int main()
{
int index;
for(index = START ; index >= END ; index = index - 1)
printf("The value of the count is now %2d\n", index);
return 0;
}
/* Result of execution
The value of the count is now 7
The value of the count is now 6
The value of the count is now 5
The value of the count is now 4
The value of the count is now 3
The value of the count is now 2
The value of the count is now 1
The value of the count is now 0
The value of the count is now -1
The value of the count is now -2
The value of the count is now -3
The value of the count is now -4
The value of the count is now -5
*/
====================================================================
#include "stdio.h"
#include "string.h"
int main()
{
int index;
char string1[6], string2[6], string3[6], all_three[18];
strcpy(string1, "one");
strcpy(string2, "two");
strcpy(string3, "three");
strcpy(all_three, string1);
strcat(all_three, " ");
strcat(all_three, string2);
strcat(all_three, " ");
strcat(all_three, string3);
for(index = 0 ; index < 10 ; index = index + 1)
printf("The final string is ---> %s\n", all_three);
return 0;
}
/* Result of execution
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
The final string is ---> one two three
*/
====================================================================
#include
int main()
{
int index, array1[10], array2[10], arrays[10];
for(index = 0 ; index < 10 ; index = index + 1)
{
array1[index] = 2 + 2 * index;
array2[index] = 10 * (index + 1);
}
for(index = 0 ; index < 10 ; index = index + 1)
arrays[index] = array1[index] + array2[index];
for(index = 0 ; index < 10 ; index = index + 1)
printf("%4d %4d + %4d = %4d\n", (index + 1), array1[index],
array2[index], arrays[index]);
return 0;
}
/* Result of execution
1 2 + 10 = 12
2 4 + 20 = 24
3 6 + 30 = 36
4 8 + 40 = 48
5 10 + 50 = 60
6 12 + 60 = 72
7 14 + 70 = 84
8 16 + 80 = 96
9 18 + 90 = 108
10 20 + 100 = 120
*/
====================================================================
#include
#include
char my_string[20] = "C is neat!";
int main()
{
int index;
printf("%s\n", my_string);
for (index = 0 ; my_string[index] ; index = index + 1)
printf("%c", my_string[index]);
printf("\n");
for(index = strlen(my_string) ; index > 0 ; index = index - 1)
printf("%c", my_string[index - 1]);
printf("\n");
return 0;
}
/* Result of execution
C is neat!
C is neat!
!taen si C
*/
====================================================================
#include
#include
int main()
{
int index;
char stuff[20], *pt;
strcpy(stuff, "This is a neat test.");
pt = stuff;
for(index = 0 ; index < 20 ; index++)
{
printf("A character is ---> %c\n", *pt);
pt++;
}
return 0;
}
/* Result of execution
A character is ---> T
A character is ---> h
A character is ---> i
A character is ---> s
A character is --->
A character is ---> i
A character is ---> s
A character is --->
A character is ---> a
A character is --->
A character is ---> n
A character is ---> e
A character is ---> a
A character is ---> t
A character is --->
A character is ---> t
A character is ---> e
A character is ---> s
A character is ---> t
A character is ---> .
*/
====================================================================
#include
#include
int main()
{
int index;
char stuff[20], *pt;
strcpy(stuff, "This is a neat test.");
pt = stuff;
for(index = 0 ; index < 20 ; index++)
{
printf("A character is ---> %c\n", *pt);
pt++;
}
return 0;
}
/* Result of execution
A character is ---> T
A character is ---> h
A character is ---> i
A character is ---> s
A character is --->
A character is ---> i
A character is ---> s
A character is --->
A character is ---> a
A character is --->
A character is ---> n
A character is ---> e
A character is ---> a
A character is ---> t
A character is --->
A character is ---> t
A character is ---> e
A character is ---> s
A character is ---> t
A character is ---> .
*/
====================================================================
#include
#include
int main()
{
int index;
char stuff[20], *pt;
strcpy(stuff, "This is a neat test.");
pt = stuff + 19;
for(index = 0 ; index < 20 ; index++)
{
printf("A character is ---> %c\n", *pt);
pt--;
}
return 0;
}
/* Result of execution
A character is ---> .
A character is ---> t
A character is ---> s
A character is ---> e
A character is ---> t
A character is --->
A character is ---> t
A character is ---> a
A character is ---> e
A character is ---> n
A character is --->
A character is ---> a
A character is --->
A character is ---> s
A character is ---> i
A character is --->
A character is ---> s
A character is ---> i
A character is ---> h
A character is ---> T
*/
====================================================================
#include
#include
int main()
{
char input_char;
printf("Hit any key - to stop hit a $\n");
do
{
input_char = _getch();
printf("Input character is %c, numerical value is %3d\n",
input_char, input_char);
} while (input_char != '$');
return 0;
}
/* Result of execution
Hit any key - to stop hit a $
Input character is A, numerical value is 65
Input character is B, numerical value is 66
...
(The display depends on the input keys hit)
*/
====================================================================
/* Chapter 9 - Program 2 - SINGLEIO.C */
/* Chapter 9 - Programming exercise 2 */
#include
#include
char storage[80];
int main()
{
char c;
int index = 0;
printf("Enter any characters, terminate program with X\n");
do
{
c = _getch(); /* get a character */
if (index < 79) /* limit it to 79 characters */
{
storage[index] = c;
index++;
}
putchar(c); /* display the hit key */
} while (c != 'X');
storage[index] = 0;
printf("%s\n", storage);
printf("\nEnd of program.\n");
return 0;
}
/* Result of execution
Enter any characters, terminate program with X
(The output depends on the characters you type in.)
End of program.
*/
====================================================================
#include
int main()
{
FILE *infile, *outfile, *printer;
char infilename[25], outfilename[25];
int c;
printf("Enter input file name ----> ");
scanf("%s", infilename);
infile = fopen(infilename, "r");
printf("Enter output file name ---> ");
scanf("%s", outfilename);
outfile = fopen(outfilename, "w");
printer = fopen("PRN", "w");
do
{
c = getc(infile);
if (c != EOF)
{
putchar(c);
putc(c, outfile);
putc(c, printer);
}
} while (c != EOF);
fclose(printer);
fclose(infile);
fclose(outfile);
return 0;
}
/* Result of execution
(This program writes to the printer, a file, and the monitor.)
*/
====================================================================
#include
int main()
{
FILE *infile;
char c, infilename[25], inputline[100];
int line = 1;
printf("Enter input file name ----> ");
scanf("%s", infilename);
infile = fopen(infilename, "r");
printf("%5d", line);
do
{
c = fgets(inputline, 100, infile); /* read a line */
if (c != NULL)
{
printf("%5d %s", line, inputline);
line++;
}
} while (c != NULL);
fclose(infile);
return 0;
}
/* Result of execution
(You will get a listing of the file on the monitor with line numbers)
*/
====================================================================
/* Chapter 10 - Program 7 */
#include
int main()
{
FILE *fp1;
char oneword[100], filename[25];
char *c;
printf("Enter filename -> ");
scanf("%s", filename); /* read the desired filename */
fp1 = fopen(filename, "r");
if (fp1 == NULL)
{
printf("File doesn't exist\n");
exit (1);
}
else
{
do
{
c = fgets(oneword, 100, fp1); /* get a line from the file */
if (c != NULL)
printf("%s", oneword); /* display it on the monitor */
} while (c != NULL); /* repeat until NULL */
}
fclose(fp1);
return 0;
}
/* Result of execution
(The output depends on weather you type in a good filename.)
*/
====================================================================
#include
#include
struct
{
char what[25];
int legs, arms;
} object[6];
int main()
{
int index;
strcpy(object[0].what, "human being");
object[0].legs = 2;
object[0].arms = 2;
strcpy(object[1].what, "dog");
object[1].legs = 4;
object[1].arms = 0;
strcpy(object[2].what, "television set");
object[2].legs = 4;
object[2].arms = 0;
strcpy(object[3].what, "chair");
object[3].legs = 4;
object[3].arms = 2;
strcpy(object[4].what, "centipede");
object[4].legs = 100;
object[4].arms = 0;
strcpy(object[5].what, "spider");
object[5].legs = 6;
object[5].arms = 0;
for(index = 0 ; index < 6 ; index++)
{
printf("A %s has %d legs and %d arms.\n", object[index].what,
object[index].legs, object[index].arms);
}
return 0;
}
/* Result of execution
A human being has 2 legs and 2 arms.
A dog has 4 legs and 0 arms.
A television set has 4 legs and 0 arms.
A chair has 4 legs and 2 arms.
A centipede has 100 legs and 0 arms.
A spider has 6 legs and 0 arms.
*/
====================================================================
#include
#include
struct
{
char what[25];
int legs, arms;
} object[6], *point;
int main()
{
int index;
strcpy(object[0].what, "human being");
object[0].legs = 2;
object[0].arms = 2;
strcpy(object[1].what, "dog");
object[1].legs = 4;
object[1].arms = 0;
strcpy(object[2].what, "television set");
object[2].legs = 4;
object[2].arms = 0;
strcpy(object[3].what, "chair");
object[3].legs = 4;
object[3].arms = 2;
strcpy(object[4].what, "centipede");
object[4].legs = 100;
object[4].arms = 0;
strcpy(object[5].what, "spider");
object[5].legs = 6;
object[5].arms = 0;
point = object;
for(index = 0 ; index < 6 ; index++)
{
printf("A %s has %d legs and %d arms.\n", point->what,
point->legs, point->arms);
point++;
}
return 0;
}
/* Result of execution
A human being has 2 legs and 2 arms.
A dog has 4 legs and 0 arms.
A television set has 4 legs and 0 arms.
A chair has 4 legs and 2 arms.
A centipede has 100 legs and 0 arms.
A spider has 6 legs and 0 arms.
*/
====================================================================
#include
#include
struct child
{
char initial; /* last name initial */
int age; /* childs age */
int grade; /* childs grade in school */
} *boy, *girl;
int main()
{
boy = (struct child *)malloc(sizeof(struct child));
boy->initial = 'R';
boy->age = 15;
boy->grade = 75;
girl = (struct child *)malloc(sizeof(struct child));
girl->age = boy->age - 1; /* she is one year younger */
girl->grade = 82;
girl->initial = 'H';
printf("%c is %d years old and got a grade of %d\n",
girl->initial, girl->age, girl->grade);
printf("%c is %d years old and got a grade of %d\n",
boy->initial, boy->age, boy->grade);
return 0;
}
/* Result of execution
H is 14 years old and got a grade of 82
R is 15 years old and got a grade of 75
*/
#include
#include
struct child
{
char initial;
int age;
int grade;
} *kids[12];
int main()
{
int index;
for (index = 0 ; index < 12 ; index++)
{
kids[index] = (struct child *)malloc(sizeof(struct child));
kids[index]->initial = 'A' + index;
kids[index]->age = 16;
kids[index]->grade = 84;
}
kids[3]->age = kids[5]->age = 17;
kids[2]->grade = kids[6]->grade = 92;
kids[4]->grade = 57;
*kids[10] = *kids[4]; /* Structure assignment */
for (index = 0 ; index < 12 ; index++)
printf("%c is %d years old and got a grade of %d\n",
kids[index]->initial, kids[index]->age,
kids[index]->grade);
return 0;
}
/* Result of execution
A is 16 years old and got a grade of 84
B is 16 years old and got a grade of 84
C is 16 years old and got a grade of 92
D is 17 years old and got a grade of 84
E is 16 years old and got a grade of 57
F is 17 years old and got a grade of 84
G is 16 years old and got a grade of 92
H is 16 years old and got a grade of 84
I is 16 years old and got a grade of 84
J is 16 years old and got a grade of 84
E is 16 years old and got a grade of 57
L is 16 years old and got a grade of 84
*/
#include
#include
struct child
{
char initial;
int age;
int grade;
} *kids[12];
int main()
{
int index;
for (index = 0 ; index < 12 ; index++)
{
kids[index] = (struct child *)malloc(sizeof(struct child));
kids[index]->initial = 'A' + index;
kids[index]->age = 16;
kids[index]->grade = 84;
}
kids[3]->age = kids[5]->age = 17;
kids[2]->grade = kids[6]->grade = 92;
kids[4]->grade = 57;
*kids[10] = *kids[4]; /* Structure assignment */
for (index = 0 ; index < 12 ; index++)
printf("%c is %d years old and got a grade of %d\n",
kids[index]->initial, kids[index]->age,
kids[index]->grade);
return 0;
}
/* Result of execution
A is 16 years old and got a grade of 84
B is 16 years old and got a grade of 84
C is 16 years old and got a grade of 92
D is 17 years old and got a grade of 84
E is 16 years old and got a grade of 57
F is 17 years old and got a grade of 84
G is 16 years old and got a grade of 92
H is 16 years old and got a grade of 84
I is 16 years old and got a grade of 84
J is 16 years old and got a grade of 84
E is 16 years old and got a grade of 57
L is 16 years old and got a grade of 84
*/