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Swap 2 numbers using Addition and Subtraction: C

In this video tutorial we shall learn how to swap two integer numbers without using a temporary variable and by simply making use of addition and subtraction.

 
#include < stdio.h >

int main()
{
    int a, b;

    printf("Enter 2 integer numbers for, a and b\n");
    scanf("%d %d", &a, &b);

    printf("You entered a = %d and b = %d\n", a ,b);

    a = a + b;
    b = a - b;
    a = a - b;

    printf("After swapping a = %d, b = %d\n", a, b);

    return 0;
}

Output:
Enter 2 integer numbers, for a and b
30
20
You entered a = 30 and b = 20
After swapping a = 20, b = 30

Scanf(): For user input

In above c program we are asking user to enter the values for variable a and b. You can know more about scanf() method/function in this video tutorial: Using Scanf in C Program

Swap 2 numbers using only Addition and Subtraction: C

[youtube https://www.youtube.com/watch?v=mm4XJ2DEVS4]

YouTube Link: https://www.youtube.com/watch?v=mm4XJ2DEVS4 [Watch the Video In Full Screen.]

Swapping 2 Numbers In C using only addition and subtraction: Logic

In our above program we are asking user to enter integer value for a and b.
If the user enters 30 and 20 for a and b respectively. Then our program executes below logic to swap the values of variable a and b.

Step 1: Add values of a and b and store it in variable a.
i.e.,
a = a + b;
50 = 30 + 20;
So a = 50;

Step 2: Now subtract value of b from value of a and store it in variable b.
i.e.,
b = a – b;
30= 50 – 20; (value of a = 50 according to Step 1)
So value of variable b is now 30.

Step 3: Now subtract value of b from value of a and store it in variable a.
i.e.,
a = a – b;
20= 50 – 30; (Value of a = 50 from Step 1, and Value of b = 30 from Step 2)

Finally value of a = 20(from step 3) and value of b = 30(from step 2).

This is how we swap the value of variable a and b by just making use of addition and subtraction in C programming language.

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

Swap 2 Numbers Without Using a Temporary Variable: C

Today lets learn how to swap 2 integer numbers without using a temporary variable in C. We’re using arithmetic operation in our logic. We’re using addition and subtraction in this c program to swap the 2 numbers.

 
#include < stdio.h >

int main()
{
    int x = 10, y = 5;

    printf("Before swapping x = %d and y = %d\n", x, y);

    x = x + y - ( y = x );

    printf("After swapping x = %d and y = %d\n", x, y);

    return 0;
}

Output:
Before swapping x = 10 and y = 5
After swapping x = 5 and y = 10

Swap 2 Numbers Without Using a Temporary Variable: C

[youtube https://www.youtube.com/watch?v=tTzdGK5t-X4]

YouTube Link: https://www.youtube.com/watch?v=tTzdGK5t-X4 [Watch the Video In Full Screen.]

Swapping 2 Numbers In C using addition, subtraction and assignment operators: Logic

Here we take 2 variables, x and y; We store 10 in x and 5 in y.

We add the values of x(10) and y(5) and then subtract the value returned when we assign x value to y.

Note: When we assign a value to a variable, the same value is returned.
Ex: temp = (a = 10);
In this statement, when we assign 10 to a, the whole expression returns 10 and we can store it in variable temp, for our reference.

Swap 2 Numbers Using a Temporary Variable: C

Today lets learn how to swap 2 integer numbers using a temporary variable in C.

 
#include < stdio.h >

int main()
{
    int x = 10, y = 20, temp;

    printf("X = %d, Y = %d\n", x, y);
    
    temp = x;
    x    = y;
    y    = temp;

    printf("After swapping X = %d, Y = %d\n", x, y);

    return 0;
}

Output:
X = 10, Y = 20
After swapping X = 20, Y = 10

Swap 2 Numbers Using a Temporary Variable: C

[youtube https://www.youtube.com/watch?v=f_JBCYWS2uw]

YouTube Link: https://www.youtube.com/watch?v=f_JBCYWS2uw [Watch the Video In Full Screen.]

Swapping 2 Numbers In C: Logic

Here we take 3 variables, x, y and temp; We store 10 in x and 20 in y.
1. First we copy the value present in x to temp. So now, both x and temp variables have value 10.
2. Next we copy value of y to x. So now, both x and y have value 20.
3. Next, copy the value of temp to y. So now both y and temp have value 10.

Finally after executing above 3 step logic, x has value 20 and y has a value of 10 in it.

Basic Arithmetic Operations In C

Today lets learn about basic arithmetic operations in C programming language.

What we learn in this video tutorial?

We shall learn, addition, subtraction, multiplication, division and modular division in this video tutorial. And we’ll also learn how to use pow() method present in math.h library file.

 
#include < stdio.h >
#include < math.h >

int main()
{
    int   a = 10, b = 2;
    char  m = 'A', n = 'a';

    printf("\nAddition of a and b is %d\n", (a+b));
    printf("\nSubtraction of a and b is %d\n", (a-b));
    printf("\nMultiplication of a and b is %d\n", (a*b));
    printf("\nDivision of a and b is %d\n", (a/b));
    printf("\nModular Division of a and b is %d\n", (a%b));
    printf("\n3 to the power of 2 is %f\n", pow(3,2));

    printf("\nASIIC value of A and a is %d and %d\n\n", m, n);

    return 0;
}

Output:

Addition of a and b is 12
Subtraction of a and b is 8
Multiplication of a and b is 20
Division of a and b is 5
Modular Division of a and b is 0
3 to the power of 2 is 9.000000
ASIIC value of A and a is 65 and 97

Basic Arithmetic Operations In C

[youtube https://www.youtube.com/watch?v=4mjiL9uwPCg]

YouTube Link: https://www.youtube.com/watch?v=4mjiL9uwPCg [Watch the Video In Full Screen.]

Precedence and associativity of arithmetic operators

1st priority: * / %
2nd priority: + –
3rd priority: =

When there is tie between same priority operators then we check the associativity. For example, for * and /, associativity is same. i.e., left to right.

So in the expression: c = a * b + a / b;
a * b gets executed first.

ASCII values

When you try to apply Arithmetic Operation on characters(alphabets, character digits, special characters) its correspondent ASCII value gets operated on. ASCII value of A is 65 and ASCII value of a is 97. This is the reason why capital A and small letter a are treated differently in C programming language. Under the hood, they have different ASCII values.

Note 1: All the variables and constants are called operands. All the arithmetic symbols(+, -, /, *, %) are called operators. = is called assignment operator.

Note 2: Only one variable is allowed on the left hand side of the equation or expression.
Ex:
c = a + b is valid.
a + b = c is invalid.

Note 3: You can’t store a decimal value in a integer variable. So if the result of evaluation of an expression has decimal value and you’re assigning it to an integer variable, then only the integer part gets stored. Decimal part will be discarded. So be careful while choosing the data type of variables while performing arithmetic operation.

Note 4: We need to always, explicitly mention the arithematic operators.
Ex:
c = (a + b)(a – b) throws error.
c = (a + b) * (a – b); is the correct way in C programming.

Note 5: An integer value divided by an integer value gives back an integer value. A float value divided by a float value gives back a floating point value.

Note 6: Modular division gives reminder of division.
Ex:
c = 10 / 2; gives c = 5;
c = 10 % 2; give c = 0;

Also,
c = -3 % 2; gives c = -1
c = 3 % -2; gives c = 1

Modular division doesn’t take float values as its operands.
Ex: c = 3.0 % 2.0; gives error

Note 7: math.h library file has other mathematical operations related methods like: pow(), sin(), cos(), tan(), abs(), sqrt() etc.

We’ll look more arithmetic operators as and when we encounter them in programs.

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

Rules for Constructing Variable Names: C

Rules for constructing variable names are same for all the data types.

Rules for Constructing Variable Names: C

[youtube https://www.youtube.com/watch?v=sICsPcrZhQw]

YouTube Link: https://www.youtube.com/watch?v=sICsPcrZhQw [Watch the Video In Full Screen.]

Rules for constructing variable names

1. First character in a variable name must be an alphabet or an underscore( _ ).

2. Variable name can have alphabet, digits and underscore.

3. No commas, space allowed in variable name.

4. No other special symbols other than underscore is allowed.

5. C variables are case sensitive. Ex: name and Name are two different variables.

6. You can not use keywords / reserve words as variable name in C.

Valid Variable Names
_name
user_name
age20
iMac

Invalid Variable Names
9hundred
Micro soft
Apple$computers

Note: All these rules for constructing variable names apply for all the data types in C.