C Input Output - printf() and scanf() funtions

C INPUT/OUTPUT

In this tutorial, We learn about c input and output with printf() and scanf() functions, covers topics like syntax, c library in which these functions present, also take the program.

To use both functions printf() & scanf(), we have to include stdlib.h header file because these functions are predefined in stdlib.h header file. We use #include<stdlib.h> statement.

C Output

We can use output function when we have to display data on screen, write in file, or printer.

C OUTPUT

Integer Output

#include<stdlib.h>
int main() {
int x=10;
printf("int value=%d",x);
return 0;
}

We write anything inside quotations but when we use format specifier like %d, %f, %c, %s, etc. i.e. format specifier replaced with the value of variable.

In this case, printf("int value=%d",x); x is variable which store value in it then value is replaced with %d. From the above example, the output will be 
int value=10

Float Input

#include<stdlib.h>
int main() {
float x=2.5;
printf("float value=%f",x);
return 0;
}

In this case, printf("float value=%f",x); x is variable which store value in it then value is replaced with %f. 

Char Input

#include<stdlib.h>
int main() {
char ch='y';
printf("char vlaue=%c",ch);
return 0;
}

In this case, printf("char value=%c",ch); ch is variable which store value in it then value is replaced with %c. 

C Input

We can use input function when we have to take data from keyboard, files, or command line to feed in the program for further processing.

As we learn in C Data Types that it takes different types of data from users as the program required. So, Input takes with a different format specifier for different data types like int, float, char, etc.

C INPUT

Integer Input

#include<stdlib.h>
int main() {
int x;
scanf("%d",&x);
printf("int value=%d",x);
return 0;
}
we use %d format specifier in double quotations which means it stores integer data and &x contains the address of x and enter value stored in that address.

Float Input

#include<stdlib.h>
int main() {
float x;
scanf("%f",&x);
printf("float value=%f",x);
return 0;
}

we use %f format specifier in double quotations which means it takes float data.

Char Input

#include<stdlib.h>
int main() {
char ch;
scanf("%c",&ch);
printf("char vlaue=%c",ch);
return 0;
}

we use %c format specifier in quotations which means it stores character data.

Format Specifiers for Input/Output

Here I provide a list of some format specifiers

1. %d for integer
2. %f for float
3. %lf for double
4. %c for character
5. %s for string

Special Case Of String Input Output

Below code, you notice that I will not take &str with scanf() in case of string only.

#include<stdlib.h>

int main(){

char str[10];

printf("Enter String str:");

scanf("%s",str);

printf("String str: %s",str);

return 0;

}

Because C does not have a string type, String is just an array of characters and an array variable stores the address of the first index location.