C Basics

#4. Basic Input and Output in C

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C language has standard libraries that allow input and output in a program. The stdio.h or standard input output library in C that has methods for input and output.

scanf()

The scanf() method, in C, reads the value from the console as per the type specified.

Syntax:

scanf(“%X”, &variableOfXType); where %X is the format specifier in C. 
It is a way to tell the compiler what type of data is in a variable and 
& is the address operator in C, which tells the compiler to change 
the real value of this variable, stored at this address in the memory.

printf()

The printf() method, in C, prints the value passed as the parameter to it, on the console screen.

Syntax:

printf(“%X”, variableOfXType); where %X is the format specifier in C. 
It is a way to tell the compiler what type of data is in a variable and 
& is the address operator in C, which tells the compiler to change 
the real value of this variable, stored at this address in the memory.

How to take the input and output of basic types in C?

The basic type in C includes types like int, float, char, etc. Inorder to input or output the specific type, the Xin the above syntax is changed with the specific format specifier of that type. The Syntax for input and output for these are:

• Integer:

Input: scanf("%d", &intVariable);
Output: printf("%d", intVariable);

• Float:

Input: scanf("%f", &floatVariable);
Output: printf("%f", floatVariable);

• Character:

Input: scanf("%c", &charVariable);
Output: printf("%c", charVariable);

/ C program to show input and output

#include <stdio.h>

int main()

{
 // Declare the variables
 int num;
 char ch;
 float f;

 // --- Integer ---
 // Input the integer
 printf("Enter the integer: ");
 scanf("%d", &num);
 // Output the integer
 printf("\nEntered integer is: %d", num);

 // --- Float ---
 //For input Clearing buffer
 while((getchar()) != '\n');
 // Input the float
 printf("\n\nEnter the float: ");
 scanf("%f", &f);
 // Output the float
 printf("\nEntered float is: %f", f);

 // --- Character ---
 // Input the Character
 printf("\n\nEnter the Character: ");
 scanf("%c", &ch);
 // Output the Character
 printf("\nEntered character is: %c", ch);

 return 0;
}

Output:

Enter the integer: 10
Entered integer is: 10

Enter the float: 2.5
Entered float is: 2.500000

Enter the Character: A
Entered Character is: A

How to take the input and output of advanced type in C?

The advanced type in C includes types like String. In order to input or output the string type, the X in the above syntax is changed with the %s format specifier. The Syntax for input and output for String is:

Input: scanf("%s", stringVariable);
Output: printf("%s", stringVariable);

Example:

// C program to show input and output

#include <stdio.h>

int main()
{
 // Declare string variable
 // as character array
 char str[50];

 // --- String ---
 // To read a word
 // Input the Word
 printf("Enter the Word: ");
 scanf("%s\n", str);
 // Output the Word
 printf("\nEntered Word is: %s", str);

 // --- String ---
 // To read a Sentence
 // Input the Sentence
 printf("\n\nEnter the Sentence: ");
 scanf("%[^\n]\ns", str);
 // Output the String
 printf("\nEntered Sentence is: %s", str);

 return 0;
}

Output:

Enter the Word: DoctorWho
Entered Word is: DoctorWho

Enter the Sentence: Doctor Eyob is The Best Teacher
Entered Sentence is: Doctor Eyob is The Best Teacher

Learning to Program in C

Upcoming C Basics: Escape sequences

Feel free to look back on C Introduction: “Hello, World!”

C Introduction