Input Functions

3 basic types of input functions that receives any value entered from the keyboard (standard input stream).

• getchar()
• gets()
• scanf()

getchar()
This function receives a character type data from the keyboard and stores into a char type variable.
Function syntax:

char variable = getchar();

Example:(outputs in bold are what the user has input)

#include< stdio.h>
int main()
{
char gender;
//prompt for user input
printf("Enter your gender:");
//input function to store data from keyboard into variable gender
gender = getchar();
//displays the gender.
printf("\nGender = %c", gender);

return 0;
}

Output:
Enter your gender:M
Gender = M


gets()
This function receives a string of characters from the keyboard and stores into a character array type variable. Note that the array must be bigger than the number of characters you are going to input.

Function syntax:

gets(char array[]);

Example:

#include< stdio.h>
int main()
{
//declare a character array to store multiple
//letters to form a word.
char name[21];

//prompts user to input data
printf("Enter your name:");
//get the data from keyboard and store into
//variable 'name'
gets(name);
//displays the content of the variable name
printf("\n Your name is %s", name);
return 0;
}

Output:
Enter your name:Programmer
Your name is Programmer

scanf()
This function is used to accept anything, integer numbers, decimal numbers, characters, and character arrays(string).

Function syntax:
scanf("placeholders", inputlist);

Placeholders tell the function what kind of data will be input, and the input list contains which variable to store the data from keyboard into it.

Example:

#include< stdio.h>
int main()
{
//declare int type variable
int mark;
//prompt user to enter mark
printf("Enter your mark: ");
//assigns the value into the variable mark
scanf("%d", &mark);
//display content of variable mark
printf("\nYour mark is %d", mark);
}

Output:
Enter your mark: 89
Your mark is 89

Placeholders will be explained in more detail in the next post.