In this article, you will learn-
- 1 C Input-Output (I/O)
- 1.1 C Output
- 1.2 Example 1: C Output
- 1.3 Example 2: Integer Output
- 1.4 Example 3: float and double Output
- 1.5 Example 4: Print Characters
- 1.6 C Input
- 1.7 Example 5: Integer Input/Output
- 1.8 Example 6: Float and Double Input/Output
- 1.9 Example 7: C Character I/O
- 1.10 Example 8: ASCII Value
- 1.11 I/O Multiple Values
- 1.12 Format Specifiers for I/O
C Input-Output (I/O)
In this tutorial, you will learn how to use scanf() function to take input from the user, and printf() function to show output to the client.
C Output
In C programming, printf() is one of the main output function. The capacity sends an arranged yield to the screen. For instance,
Example 1: C Output
#include <stdio.h> int main() { // Displays the string inside quotations printf("C Programming"); return 0; }
Output
C Programming
How does this program work?
All valid C programs must contain the main() function. The code execution begins from the start of the main() function.
The printf() is a library function to send formatted output to the screen. The function prints the string inside quotations.
To use printf() in our program, we need to include stdio.h header file using the #include <stdio.h> statement.
The return 0; statement inside the main() function is the “Exit status” of the program. It’s optional.
Example 2: Integer Output
#include <stdio.h> int main() { int testInteger = 5; printf("Number = %d", testInteger); return 0; }
Output
Number = 5
We use the %d design specifier to print int types. Here, the %d inside the citations will be supplanted by the estimation of testInteger.
Example 3: float and double Output
#include <stdio.h> int main() { float number1 = 13.5; double number2 = 12.4; printf("number1 = %f\n", number1); printf("number2 = %lf", number2); return 0; }
Output
number1 = 13.500000 number2 = 12.400000
To print float, we use the %f format specifier. Similarly, we use %lf to print double values.
Example 4: Print Characters
#include <stdio.h> int main() { char chr = 'a'; printf("character = %c.", chr); return 0; }
Output
character = a
To print char, we use the %c format specifier.
C Input
In C programming, scanf() is one of the commonly used functions to take input from the client. The scanf() function reads formatted input from the standard input such as keyboards.
Example 5: Integer Input/Output
#include <stdio.h> int main() { int testInteger; printf("Enter an integer: "); scanf("%d", &testInteger); printf("Number = %d",testInteger); return 0; }
Output
Enter an integer: 4 Number = 4
Here, we have used the %d design specifier inside the scanf() capacity to take int contribution from the client. when the client enters a number, it is put away in the testInteger variable.
Notice, that we have used &testInteger inside scanf(). It is on the grounds that &testInteger gets the location of testInteger, and the value entered by the user is stored in that address.
Example 6: Float and Double Input/Output
#include <stdio.h> int main() { float num1; double num2; printf("Enter a number: "); scanf("%f", &num1); printf("Enter another number: "); scanf("%lf", &num2); printf("num1 = %f\n", num1); printf("num2 = %lf", num2); return 0; }
Output
Enter a number: 12.523 Enter another number: 10.2 num1 = 12.523000 num2 = 10.200000
We use %f and %lf format specifier for float and double respectively.
Example 7: C Character I/O
#include <stdio.h> int main() { char chr; printf("Enter a character: "); scanf("%c",&chr); printf("You entered %c.", chr); return 0; }
Output
Enter a character: g You entered g.
When a character is entered by the client in the above program, the character itself isn’t put away. Rather, a whole number worth (ASCII value) is stored.
What’s more, when we show that worth utilizing %c text design, the entered character is shown. In the event that we use %d to show the character, it’s ASCII value is printed.
Example 8: ASCII Value
#include <stdio.h> int main() { char chr; printf("Enter a character: "); scanf("%c", &chr); // When %c is used, a character is displayed printf("You entered %c.\n",chr); // When %d is used, ASCII value is displayed printf("ASCII value is % d.", chr); return 0; }
Output
Enter a character: g You entered g. ASCII value is 103.
I/O Multiple Values
Here’s how you can take multiple inputs from the user and display them.
#include <stdio.h> int main() { int a; float b; printf("Enter integer and then a float: "); // Taking multiple inputs scanf("%d%f", &a, &b); printf("You entered %d and %f", a, b); return 0; }
Output
Enter integer and then a float: -3 3.4 You entered -3 and 3.400000
Format Specifiers for I/O
As you can see from the above examples, we use
%d for int
%f for float
%lf for double
%c for char
Here’s a list of commonly used C data types and their format specifiers.
Data Type | Format Specifier |
int | %d |
char | %c |
float | %f |
double | %lf |
short int | %hd |
unsigned int | %u |
long int | %li |
long long int | %lli |
unsigned long int | %lu |
unsigned long long int | %llu |
signed char | %c |
unsigned char | %c |
long double | %Lf |
Please feel free to give your comment if you face any difficulty here.
For more Articles click on the below link.