In the C programming language, the gets function is frequently used to capture an entire line of input from the standard input stream and place it into the memory location pointed to by the specified string. This function enables the program to collect characters from the input stream until it reaches either a newline character or the end-of-file (EOF) marker. Subsequently, the newline character is substituted with a null terminator, effectively creating a C-style string that is then stored in the designated memory location.
Syntax:
It has the following syntax:
gets(string);
In this particular syntax,
- String: serves the purpose of storing the input in a character array format.
Return Value:
The outcome of the gets function is determined by the success or failure of the operation. In cases of success, it will return the identical pointer str. Conversely, if the operation encounters a failure or encounters an EOF condition, it will return NULL.
Simple C gets function Example
Here, we are using an example to demonstrate the gets function in C programming.
Example
#include<stdio.h>
void main () // main function
{
char s[50];
printf("Enter the string: ");
gets(s);
printf("You entered %s",s);
}
Output:
Enter the string: Hello! Welcome to Logic Practice
You entered Hello! Welcome to Logic Practice
Explanation:
In this instance, we're illustrating the process of receiving user input by utilizing the gets function to collect input and save it in the character array s. Subsequently, gets reads a complete line of text, spaces included, until it encounters a newline character or EOF. Upon entering the string, it displays the inputted string through the printf function. Nevertheless, gets is considered unsafe and obsolete due to its susceptibility to buffer overflow. Consequently, contemporary programs are advised to opt for the fgets function over gets for improved security.
Features of the gets function in C
There are several features of the gets function in C. Some of them are as follows:
- The gets function in C is commonly used to read an entire line of text, including spaces, until it encounters the newline character or EOF.
- This function doesn't perform boundary checking, which makes it unsafe and insecure because it can cause a buffer overflow in the program.
- It allows us to store the input string in the character array.
- It is declared in the stdio.h header file. It also returns a pointer to the string read.
- It helps to automatically remove the newline character. Therefore, the stored string doesn't contain \n.
C puts function
In the C programming language, the puts function bears resemblance to the printf function. Its primary purpose is to display a string on the standard output (usually the screen) along with a newline character. Unlike printf, puts appends a newline by default and doesn't support formatting. It accepts a single string input and prints it as is. Upon successful execution, puts returns a non-negative value; otherwise, it returns EOF to indicate failure.
Syntax:
It has the following syntax:
puts(string);
In this format,
- String denotes the null-terminated character sequence that will be displayed on the screen.
Return Value:
The outcome of the puts function varies based on the outcome of the operation. When the operation succeeds, it provides a non-negative value; otherwise, it returns an EOF (End-of-File).
C Simple puts Function Example
Here, let's consider an example to demonstrate the puts function in the C programming language.
Example
#include<stdio.h>
#include <string.h>
int main(){ // main function
char name[50];
printf("Enter your name: ");
gets(name); //reads string from user
printf("Your name is: ");
puts(name); //displays string
return 0;
}
Output:
Enter your name: Albert Peter
Your name is: Albert Peter
Explanation:
In this particular instance, it requests the user to input their name and saves it in a character array. The gets function retrieves the entire line of input, spaces included, and saves it in the name variable. Subsequently, the puts function is employed to display the inputted name on the screen.
C Example using both gets and puts Function
In this instance, we will illustrate the implementation of the gets function and puts function in the C programming language.
Example
#include <stdio.h>
int main() { // main function
char st[55]; // declaration of a character array
printf("Enter a string: ");
gets(st); // using the gets() function to read a string from user
puts("You entered the String:");
puts(st); // using the puts() function to print the string
return 0;
}
Output:
Enter a string: Hello! This is Logic Practice
You entered the String:
Hello! This is Logic Practice
Explanation:
In this provided illustration, we are utilizing the gets function to read a string, allowing us to input values, even those with spaces. Upon inputting the string with gets, it automatically appends a newline after the string. Subsequently, the output is displayed on the screen.
Features of the puts function in C
There are several features of the puts function in C. Some of them are as follows:
- The puts function is commonly used to print a string to the standard output, which is followed by an automatic newline character in the C program.
- It is mainly declared in the stdio.h header file. It returns a non-negative integer on success or EOF (End-Of-File) on operation failure.
- It helps to accept only one argument, which should be a null-terminated string.
- It is a simple and safer function than the printf function because it does not need any formatting specifiers.
- It is also useful to print the output quickly without requiring any format specifier.
Conclusion:
In summary, the gets and puts functions in C offer a straightforward and efficient approach for managing simple string input and output operations. The gets function is frequently employed for reading a complete line of text, which may include spaces. In contrast, the puts function is typically utilized for displaying a string and automatically appending a newline character. Despite their user-friendly nature, the gets function is deemed insecure due to its lack of buffer limit checks, potentially leading to overflow problems. In general, familiarizing oneself with the gets and puts functions is beneficial for grasping essential string manipulation techniques and handling console input/output tasks in C.
C gets and puts Function FAQs
1) What is the gets function in C?
In C programming, the gets function allows users to input a sequence of characters terminated by the Enter key. This function is frequently employed for reading a complete line of text, including whitespace characters.
2) What is the puts function in C?
The puts function within the C programming language bears resemblance to the printf function. It is frequently employed for displaying a string and appending a newline character automatically.
The gets function is considered unsafe in C because it does not perform any bounds checking on the input provided by the user. This can lead to buffer overflow vulnerabilities, where the input can overwrite memory locations beyond the allocated space for the input buffer. This poses a serious security risk as it can be exploited by malicious users to execute arbitrary code or manipulate program behavior. It is recommended to use safer alternatives like fgets which allows specifying the maximum number of characters to read.
In C programming, the gets function does not validate the buffer size, leading to potential buffer overflow vulnerabilities, rendering it unsafe for use in programs. This lack of size checking resulted in its exclusion from the C11 standard.
4) Is manual addition of a newline required by the puts function in C?
No, the puts function in C does not require the user to manually append a newline character. This is because the puts function inherently adds a newline at the end of the displayed string.
5) Is there a return value from the puts function in C?
Yes, the outcome of the puts function is determined by whether the operation is successful or not. In case of success, it yields a non-negative value, while in case of failure, it yields an EOF (End-of-File) signal.