===================Example 1 ===================
// reciprocal.c
// This example shows how to
// (1) Ask the user for a "floating point" number
// (2) get the number
// (3) Create your own function
// (4) Print a floating point number
// When you try this program, test it out with various numbers. At least try
// 0.25 -- super simple
// 3 -- watch what happens with a repeating decimal
// 2e25 -- a huge number. 2x10^25
// 2e-25 -- a tiny number
// Also try typing in nonsense, such as "hello"
// Compile command for this code c version:
// gcc -Wall -W -Werror reciprocal.c -o reciprocal
// Compile command for this code c++ version:
// g++ -Wall -W -Werror reciprocal.c -o reciprocal
// To run the program type:
// ./reciprocal
// More info: "double" tells the compiler that we want decimal number. Not integers.
#include <stdio.h>
// Create a new function which will compute the reciprocal of a number.
double reciprocal(double x) // x is the input
{
double a; // a is the output
a = 1/x;
return(a);
}
int main()
{
double your_number;
double the_reciprocal;
printf("Give me a number: ");
scanf("%lf",&your_number);
// "&" is used because its the memory address of "your_number" that matters
// "%lf" means that the user will type in a "floating" style number (a decimal)
// See http://www.cs.utah.edu/~zachary/isp/tutorials/io/io.html
printf("OK, you gave me %g\n",your_number); // Always use %g for displaying "double" numbers
the_reciprocal = reciprocal(your_number);
printf("The reciprocal is %g\n",the_reciprocal);
printf("The reciprocal, with more precision, is %2.18g\n",the_reciprocal);
return(0);
}
===================Example 2 ===================
// reciprocal_for_dummy.c
// This example shows how to
// (1) Ask the user for a "floating point" number
// (2) get the number
// (3) Create your own function
// (4) Print a floating point number
// When you try this program, test it out with various numbers. At least try
// 0.25 -- super simple
// 3 -- watch what happens with a repeating decimal
// 2e25 -- a huge number. 2x10^25
// 2e-25 -- a tiny number
// Also try typing in nonsense, such as "hello"
// Compile command for this code c version:
// gcc -Wall -W -Werror reciprocal_for_dummy.c -o reciprocal_for_dummy
// Compile command for this code c++ version:
// g++ -Wall -W -Werror reciprocal_for_dummy.c -o reciprocal_for_dummy
// To run the program type:
// ./reciprocal_for_dummy
// More info: "double" tells the compiler that we want decimal number. Not integers.
#include <stdio.h>
// Create a new function which will compute the reciprocal of a number.
double reciprocal_for_dummy(double x) // x is the input
{
double a; // a is the output
a = 1/x;
return(a);
}
int main()
{
double your_number;
double new_number;
int OK_number;
do {
printf("Give me a number: ");
OK_number = scanf("%lf",&your_number); // If the user typed in an OK number, then OK_nummber will be 1
// "&" is used because its the memory address of "your_number" that matters
// "%lf" means that the user will type in a "floating" style number (a decimal)
// See http://www.cs.utah.edu/~zachary/isp/tutorials/io/io.html
// printf("OK_number=%d\n",OK_number);
if (OK_number != 1) {
printf("You dummy. Give me a valid number!!!\n");
scanf ("%*[^\n]"); // Flush out all the junk that the dummy typed in.
// See http://home.datacomm.ch/t_wolf/tw/c/getting_input.html
}
} while (OK_number != 1);
printf("OK, you gave me %g\n",your_number); // Always use %g for displaying "double" numbers
new_number = reciprocal_for_dummy(your_number);
printf("The reciprocal is %g\n",new_number);
printf("The reciprocal, with more precision, is %2.18g\n",new_number);
return(0);
}
===================Example 3 ===================
// factorial_for_dummy.c
// This example shows how to
// (1) Ask the user for an integer number
// (2) get the number
// (3) Create your own function - in this example the Factorial function. Factorial x is written x!
// Factorial is like this: 3!=2x3=6, 4!=2x3x4=24, 5!=2x3x4x5=120, etc.
// (4) Print it out.
// When you try this program, test it out with various numbers. At least try
// 5
// 16
// 17 (You will notice that the result is wrong for 17. Why?)
// Also try typing in nonsense, such as "hello"
// Try 0 and negative numbers. Does it work?
// Compile command for this code c version:
// gcc -Wall -W -Werror factorial_for_dummy.c -o factorial_for_dummy
// Compile command for this code c++ version:
// g++ -Wall -W -Werror factorial_for_dummy.c -o factorial_for_dummy
// To run the program type:
// ./factorial_for_dummy
//#include <stdio.h> // Include the standard input-output library. Needed for keyboard.
// Create a new function which will compute the reciprocal of a number.
int factorial(int x) // x is the input
{
int loop_count;
int a; // a is the output
a=1;
for (loop_count=2; loop_count < x+1;loop_count++) a=a*loop_count;
return(a);
}
int main()
{
int your_number;
int new_number;
int OK_number;
do {
printf("Give me a number: ");
OK_number = scanf("%d",&your_number); // Get the number from the keyboard
if (OK_number != 1) {
printf("You dummy. Give me a valid number!!!\n");
scanf ("%*[^\n]"); // Flush out all the junk that the dummy typed in.
// See http://home.datacomm.ch/t_wolf/tw/c/getting_input.html
}
} while (OK_number != 1);
printf("OK, you gave me %d\n",your_number); // Use %d for displaying integer numbers
new_number = factorial(your_number);
printf("%d!=%d\n",your_number,new_number);
return(0);
}
===================Example 4 ===================
// bits_in_a_number.c
// This program asks the user to type in a number, and then it prints it out in binary
// Compile command for this code c version:
// gcc -Wall -W -Werror bits_in_a_number.c -o bits_in_a_number
// Compile command for this code c++ version:
// g++ -Wall -W -Werror bits_in_a_number.c -o bits_in_a_number
// To run the program type:
// ./bits_in_a_number
#include <stdio.h> // Include the standard input-output library. Needed for keyboard and printing.
int main()
{
int your_number;
int bit_mask; //Used to select individual bits. It will be all zeroes, except for desired bit.
int bit_num;
int OK_number;
do {
printf("Give me a number: ");
OK_number = scanf("%d",&your_number); // Get the number from the keyboard
if (OK_number != 1) {
printf("You dummy. Give me a valid number!!!\n");
scanf ("%*[^\n]"); // Flush out all the junk that the dummy typed in.
// See http://home.datacomm.ch/t_wolf/tw/c/getting_input.html
}
} while (OK_number != 1);
printf("OK, you gave me %d\n",your_number); // Use %d for displaying integer numbers
for (bit_num=16; bit_num >= 0; bit_num--) {
bit_mask = 1 << bit_num;
printf("%d ",bit_mask);
if ((bit_mask & your_number) == 0) printf("0"); else printf("1"); //bitwise "and". Only the selected bit
// comes through.
printf("\n");
}
printf("\n");
return(0);
}
