Basic Input and Output in C

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 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 X in 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);
    

Please refer Format specifiers in C for more examples.

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// 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 ---
  
    // 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 integer is: %c", ch);
  
    return 0;
}

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Output:

Enter the integer: 10
Entered integer is: 10

Enter the float: 2.5
Entered float is: 2.500000

Enter the Character: A
Entered integer is: A

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

The advanced type in C includes type 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:

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// 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", 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]s", str);
  
    // Output the String
    printf("\nEntered Sentence is: %s", str);
  
    return 0;
}

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Output:

Enter the Word: GeeksForGeeks
Entered Word is: GeeksForGeeks

Enter the Sentence: Geeks For Geeks
Entered Sentence is: Geeks For Geeks


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