# Program to implement Logic Gates

• Difficulty Level : Easy
• Last Updated : 31 Oct, 2019

A Logic gate is an elementary building block of any digital circuits. It takes one or two inputs and produces output based on those inputs. Outputs may be high (1) or low (0). Logic gates are implemented using diodes or transistors. It can also be constructed using vacuum tubes, electromagnetic elements like optics, molecule etc. In a computer, most of the electronic circuits are made up logic gates. Logic gates are used to create a circuit that performs calculations, data storage or shows off object-oriented programming especially the power of inheritance.

There are seven basic logic gates defined, these are:

1. AND gate,
2. OR gate,
3. NOT gate,
4. NAND gate,
5. NOR gate,
6. XOR gate and
7. XNOR gate.

Below are the brief details about them along with their implementation:

1. AND Gate
The AND gate gives an output of 1 if both the two inputs are 1, it gives 0 otherwise.

Below are the programs to implement AND gate using various methods:

1. Using product method.
2. Using if else condition.
3. Using “and (&)” operator.

## Product Method

 // C program implementing the AND gate// through product method.  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, product;      for (i = 0; i < 5; i++) {          // using product method        product = a[i] * b[i];          printf("\n %d AND %d = %d",               a[i], b[i], product);    }}

## & Operator

 // C program implementing the AND gate// using & operator  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, and_ans;      for (i = 0; i < 5; i++) {          // using the & operator        and_ans = a[i] & b[i];          printf("\n %d AND %d = %d",               a[i], b[i], and_ans);    }}

## If-Else

 // C program implementing the AND gate// using if and else condition  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, ans;      for (i = 0; i < 5; i++) {        if (a[i] == 0 && b[i] == 0)            ans = 0;          else if (a[i] == 0 && b[i] == 1)            ans = 0;          else if (a[i] == 1 && b[i] == 0)            ans = 0;        else            ans = 1;          printf("\n %d AND %d = %d",               a[i], b[i], ans);    }}

Output:

1 AND 0 = 0
0 AND 1 = 0
1 AND 1 = 1
0 AND 0 = 0
1 AND 0 = 0

2. OR Gate
The OR gate gives an output of 1 if either of the two inputs are 1, it gives 0 otherwise.

Below are the programs to implement AND gate using various methods:

1. Using + operator.
2. Using | operator.
3. Using || operator.
4. Using if else.

## + Operator

 // C program implementing the OR gate// using + operator  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, or_ans;      for (i = 0; i < 5; i++) {          // using the + operator        if (a[i] + b[i] > 0)            or_ans = 1;        else            or_ans = 0;          printf("\n %d AND %d = %d",               a[i], b[i], or_ans);    }}

## | Operator

 // C program implementing the OR gate// using | operator  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, or_ans;      for (i = 0; i < 5; i++) {          // using the | operator        or_ans = a[i] | b[i];          printf("\n %d AND %d = %d",               a[i], b[i], or_ans);    }}

## || Operator

 // C program implementing the OR gate// using || operator  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, or_ans;      for (i = 0; i < 5; i++) {          // using the || operator        or_ans = a[i] || b[i];          printf("\n %d AND %d = %d",               a[i], b[i], or_ans);    }}

## If-Else

 // C program implementing the OR gate// using if else  #include #include   int main(){    int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, or_ans;      for (i = 0; i < 5; i++) {          // using the if-else conditions        if (a[i] == 0 && b[i] == 0)            or_ans = 0;        else            or_ans = 1;          printf("\n %d AND %d = %d",               a[i], b[i], or_ans);    }}

Output:

1 AND 0 = 1
0 AND 1 = 1
1 AND 1 = 1
0 AND 0 = 0
1 AND 0 = 1

3. NAND Gate
The NAND gate (negated AND) gives an output of 0 if both inputs are 1, it gives 1 otherwise.

Below are the programs to implement NAND gate using various methods:

1. Using if else.
2. Using Complement of the product.

## If-Else

 // C program implementing the NAND gate  #include #include   int main(){      int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, ans;      for (i = 0; i < 5; i++) {        if (a[i] == 1 && b[i] == 1)            ans = 0;        else            ans = 1;        printf("\n %d NAND %d = %d",               a[i], b[i], ans);    }}

## Complement of the product

 // C program implementing the NAND gate  #include #include   int main(){      int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, ans;      for (i = 0; i < 5; i++) {        ans = !(a[i] * b[i]);        printf("\n %d NAND %d = %d",               a[i], b[i], ans);    }}

Output:

1 NAND 0 = 1
0 NAND 1 = 1
1 NAND 1 = 0
0 NAND 0 = 1
1 NAND 0 = 1

4. NOR Gate
The NOR gate (negated OR) gives an output of 1 if both inputs are 0, it gives 1 otherwise.

Below are the programs to implement NOR gate using various methods:

1. Using + Operator.
2. Using if else.

## + Operator

 // C program implementing the NOR gate  #include #include   int main(){      int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, ans;      for (i = 0; i < 5; i++) {        ans = !(a[i] + b[i]);        printf("\n %d NOR %d = %d",               a[i], b[i], ans);    }}

## If-Else

 // C program implementing the NOR gate  #include #include   int main(){      int a[5] = { 1, 0, 1, 0, 1 };    int b[5] = { 0, 1, 1, 0, 0 };    int i, ans;      for (i = 0; i < 5; i++) {        if (a[i] == 0 && b[i] == 0)            ans = 1;        else            ans = 0;        printf("\n %d NOR %d = %d",               a[i], b[i], ans);    }}

Output:

1 NOR 0 = 0
0 NOR 1 = 0
1 NOR 1 = 0
0 NOR 0 = 1
1 NOR 0 = 0

5. NOT Gate

It acts as an inverter. It takes only one input. If the input is given as 1, it will invert the result as 0 and vice-versa.

Below are the programs to implement NOT gate using various methods:

1. Using ! Operator.
2. Using if else.

## If-Else

 // C program implementing the NOT gate  #include #include   int main(){      int a[5] = { 1, 0, 1, 0, 1 };    int i, ans;      for (i = 0; i < 5; i++) {        if (a[i] == 0)            ans = 1;        else            ans = 0;        printf("\n  NOT %d = %d", a[i], ans);    }}

## ! Operator

 // C program implementing the NOT gate  #include #include   int main(){      int a[5] = { 1, 0, 1, 0, 1 };    int i, ans;      for (i = 0; i < 5; i++) {        ans = !(a[i]);        printf("\n  NOT %d = %d", a[i], ans);    }}

Output:

NOT 1 = 0
NOT 0 = 1
NOT 1 = 0
NOT 0 = 1
NOT 1 = 0

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