Question

Using C programming language

Question 1 a) through m)

Exercise #1: Write a C program that contains the following steps (make sure all variables are int). Read carefully each step as they are not only programming steps but also learning topics that explain how functions in C really work. a. Ask the user for a number between 10 and 99. Write an input validation loop to make sure it is within the prescribed range and ask again if not. b. Commenting out the existing coding, write the code to divide a two digit integer number by 10 (pick any number you want between 10 and 99; hard code it right into the program rather than input it). Output the result as an integer. Try this with a few different initial numbers. For example, 59 would give an output of 5. c. Next write the code to find the remainder when a two digit number (again, hard code it into your program) is divided by 10 [note that this is done in a single statement]. Output the result as an integer. Try this with a few different numbers. For example, 59 would give an output of 9. d. Comment the code from steps 4 and 5 out of your program, and put the coding to find the number of 10's in a number into a user defined (helper) function named f1. Set the initial number in a variable named x in the main function and print it out to check that it was set correctly). Your code will then pass x to a variable named y in f1 - the syntax for the call is of course f1(x); . (That is, you are copying the After f1 returns, the main function should print the returned value. You should see the original number printed from the main function and the returned number of 10's in that original number, also printed from the main function. Try this with a couple of different initial numbers. e. Repeat step 6 but this time put the coding of the step 5 into another user defined (helper) function named f2. Again use y as the name of the parameter in f2; it will not get confused with the y in f1 - they are declared in separate functions and are thus completely different variables. (fi has its own y and f2 has its own y.) f2 should return the remainder when the passed (copied) number in y is divided by 10. After the setting of the initial number and printing it to check it, the main function should invoke (call) f2, and after f2 returns the main function should print the returned value. You should see the original number printed from the main function and the returned remainder when that original number is divided by 10, also printed from the main function. Try this with a couple of different initial numbers.

Answer 1

Note:

1. Change the variable names as per the requirement.

2. Comment the code that you do not need, every part is well separated.

#include <stdio.h>

int f1(int x)

{

return (x%100)/10;

}

int f2(int x)

{

return (x%10);

}

void f3(int *x)

{

printf("In f3: %d\n",(*x));

}

void f3_modified(int *x)

{

(*x) = (*x) + 4;

}

void f4(int y, int* addr1, int* addr2)

{

*addr1 = (y%100)/10;

*addr2 = (y%10);

}

int main()

{

// part(a)

while(1)

{

printf("Enter a number between 10 and 99:");

int x;

scanf("%d",&x);

if(x >= 10 && x <= 99)

{

break;

}

else

{

printf("Not in range!\n");

}

}

printf("\n");

// part(b)

int var1 = 59;

int out1 = var1/10;

printf("out1: %d\n",out1);

printf("\n");

// part(c)

int var2 = 59;

int out2 = var2%10;

printf("out2: %d\n",out2);

printf("\n");

// part(d);

int var3 = 145;

printf("var3: %d\n",var3);

int out3 = f1(var3);

printf("f1(%d) = %d\n",var3,out3);

printf("\n");

// part(e)

int var4 = 1345;

printf("var4: %d\n",var4);

int out4 = f2(var4);

printf("f2(%d) = %d\n",var4,out4);

printf("\n");

// part(g)

int var5 = 25;

printf("Before calling f3() from main: %d\n",var5);

f3(&var5);

printf("After calling f3() from main: %d\n",var5);

printf("\n");

// part(h)

int var6 = 87;

printf("Before calling f3_modified() from main: %d\n", var6);

f3_modified(&var6);

printf("After calling f3_modified() from main: %d\n", var6);

printf("\n");

// part(l)

int x = 135;

int num_of_tens, remainder;

f4(x,&num_of_tens,&remainder);

printf("x = %d\n", x);

printf("number of tens = %d\n",num_of_tens);

printf("reaminder = %d\n",remainder);

}