25. C Pointers and Functions.md

C Pointers and Functions

Video Link: https://youtu.be/JYHpD9huNR4
Tutorial Link: https://www.programiz.com/c-programming/c-pointer-functions

C Pointers and Functions

#include <stdio.h>

void findValue(int* num) {

  *num = 39;
}

int main() {

  int number = 21;

  findValue(&number);
  
  printf("Number: %d", number);

  return 0;
}

Output

Number: 39

Find the square of a number

#include <stdio.h>

void findSquare(int* number) {
  
  int square = *number * *number;

  *number = square;
}

int main() {

  int number = 21;

  findSquare(&number);
  
  printf("Square is %d", number);

  return 0;
}

Output

Square is 441

Return pointers from a function

#include <stdio.h>

int* findSquare(int* number) {
  
  int square = *number * *number;

  *number = square;

  return number;
}

int main() {

  int number = 21;

  int* result = findSquare(&number);
  
printf("Result is %d", *result);

  return 0;
}

Output

Result is 441

Add two numbers

#include <stdio.h>

int* addNumbers(int* num1, int* num2, int* sum) {

  *sum = *num1 + *num2;

  return sum;
}

int main() {

  int number1 = 32;
  int number2 = 18;
  
  int sum;

  int* result = addNumbers(&number1, &number2, &sum);
  
  printf("Sum is %d", *result);

  return 0;
}

Output

Sum is 50

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Programming Task

Create a program to find the multiplication of two numbers using a function and pointers.

Here's how your program should work:

• Create a function that accepts three pointers.

• Inside the function multiply values represented by two pointers and assign the result to the address of the third pointer.

• Inside the main function, create three variables, two variables with values 13 and 9 and the third variable to store their product.

• Call the function with addresses of the 3 variables as arguments.

• Store the returned value inside a pointer and print the value pointed by the returned address.

Solution

#include <stdio.h>

int* multiplication (int* a, int* b, int* c) {
    *c = *a * *b;
    return c;
}

int main() {
    
    int num1 = 13;
    int num2 = 9;
    int multiple;
    
    int* result = multiplication(&num1, &num2, &multiple);
    
    printf("The multiplication is: %d", *result);
    
    return 0;
}

Output

The multiplication is: 117

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Programiz Quiz

Q. What type of value does the following function return?

Options:

1. Integer value
2. Address of integer variable
3. Double value
4. Address of double variable

Answer: 4