Datatype and Variable
What is Datatypes?​
Datatype is a type of information which can stored in variable. There are three primitive datatypes in c language. Let's discuss,
Integer (int)
Integer means stores whole numbers without decimal point. The size of the int datatype is 4 byte.
💻Example : 1, 2, 2253, 899, 44, 55...
Character (char)
Character is stored in a single letter. The size of the char datatype is 1 byte.
💻Example : 'r','v','s'....
Float (float)
Float means stores numbers with decimal points. The size of the float datatype is 4 bytes.
💻Example : 15.7,89.0,46.84 ....
Format Specifiers​
There are different format specifiers for each datatype.
%d = int
%f = float
%c = char
Code :
#include <stdio.h>
int main()
{
int age=10;
printf("%d",age);
return 0;
}
Output :
10
Example explanation :
In the above example, we import a standard library file #include <stdio.h>. The main() function is an entry point of the program that starts the execution of the program. We have declared a variable age that initialize with value 10 and used int datatype. Using the printf function, we display the output with format specifier %d.
Code :
#include <stdio.h>
int main()
{
int age;
age = 30;
printf("%d",age);
return 0;
}
Output :
30
Example explanation :
In the above example, we import a standard library file #include <stdio.h>. The main() function is an entry point of the program that starts the execution of the program. We have declared a variable age that initialize with value 30 and used int datatype. Using the printf function, we display the output with format specifier %d.
Code :
#include <stdio.h>
int main()
{
int age;
age = 30;
age = 50;
printf("%d",age);
return 0;
}
Output :
50
Example explanation :
In the above example, we import a standard library file #include <stdio.h>. The main() function is an entry point of the program that starts the execution of the program. We have declared a variable age that initialize with value 30 and used int datatype and again we have declared a variable age that initialize with value 50 and used int datatype. Using the printf function, we display the output with format specifier %d. In this case print sencond value of age because 2nd time we initialize 50 value.
Code :
#include <stdio.h>
int main()
{
int age;
age = 30;
printf("%d",age);
age = 50;
printf("\n %d",age);
return 0;
}
Output :
30
50
Example explanation :
In the above example, we import a standard library file #include <stdio.h>. The main() function is an entry point of the program that starts the execution of the program. We have declared age variable and datatype of that variable is int. We have declared a variable age that initialize with value 30. Using the printf function, we display the output with format specifier %d. Again we have declared a variable age that initialize with value 50. Using the printf function, we display the output with format specifier %d.
Code :
#include <stdio.h>
int main()
{
float weight=80.5;
printf("%f",weight);
return 0;
}
Output :
80.500000
Example explanaion :
In the above example, we import a standard library file #include <stdio.h>. The main() function is an entry point of the program that starts the execution of the program. We have declared a variable weight that initialize with value 80.5 and used float datatype. Using the printf function, we display the output with format specifier %f.
Code :
#include <stdio.h>
int main()
{
char alpha='c';
printf("%c",alpha);
return 0;
}
Output :
c
Example explanation :
In the above example, we import a standard library file #include <stdio.h>. The main() function is an entry point of the program that starts the execution of the program. we have declared a variable alpha that initialize with value c and used char datatype. Using the printf function, we display the output with format specifier %c.
Variable​
Variable is a container that is used to store data.
Rules of Declare Variables​
A Variable name can contain alphabates
(A to Z)(a to z), digits(0-9), underscore( _ ).Variable name cannot start with digit.
Variable name cannot use reserved keyword or special character.
Length of variable name should be less than 31 character.
How to declare variable?​
In a c language, we can declare variables using datatype. The syntax of variable declaration is
datatype variablename;
Example :
int age;
char gender;
float weight;
char, int and float these datatypes are used to declare the variable.
Case Sensitivity​
Text that is sensitive to capitalization of letters.
For example: NAME ,name,NaMe are three different.
Example : Write a program to sum of 2 variable.
Code :
#include <stdio.h>
int main() {
int a=10;
int b=20;
int c;
c=a+b;
printf("%d",c);
return 0;
}
Output :
30
Code :
#include <stdio.h>
int main() {
int val1=30;
int val2=20;
int sum;
sum=val1 + val2;
printf("%d",sum);
return 0;
}
Output :
50
Code :
#include <stdio.h>
int main() {
int val1=30, val2=20, sum;
sum=val1 + val2;
printf("%d",sum);
return 0;
}
Output :
50
Formatting Output​
Code :
#include <stdio.h>
int main()
{
int val1 = 30, val2 = 20, sum;
sum = val1 + val2;
printf("Sum = %d",sum);
return 0;
}
Output :
Sum = 50
Code :
#include <stdio.h>
int main()
{
float num = 20.5;
printf("Number is %f", num);
return 0;
}
Output :
Number is 20.500000
Code :
#include <stdio.h>
int main()
{
float weight = 80.5;
printf("Weight is %f",weight);
return 0;
}
Output :
Weight is 80.500000
Code :
#include <stdio.h>
int main() {
int a = 10;
int b = 20;
int c = a + b;
printf("a = %d b = %d",a,b);
return 0;
}
Output :
a = 10 b = 20
Code :
#include <stdio.h>
int main()
{
int val1 = 10;
int val2 = 20;
int sum = val1 + val2;
printf("Sum of %d and %d is %d",val1,val2,sum);
return 0;
}
Output :
Sum of 10 and 20 is 30
Example Explanation :
In the above example, In the 3rd line we create one variable and name of that variable is val1. In this variable, we store the value 10, which datatype is int. In the 4th line we create a second variable and name of that variable is val2. In this variable, we store the value 20, which datatype is also int. In the 5th line we create a third and name of that variable is sum. In this line we take a addition of val1 and val2. In the 6th line we used printf() function for print the sum on screen.