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Q.1)Write a program to display user details as User name,Email,Contact no,Address each on new line.

#include<stdio.h>
#include<conio.h>

void main(){

char username[25],Email[40],contact[15],add[80];
clrscr();//to be used after   
printf("Enter all your details below\n");


*//gets() function does not work after the scanf() function.
//i.e  gets() should be written on top after declaration to work.*

printf("username :");
scanf("%s",&username[0]);

printf("Enter your Address:");
gets(add);        // **←---------------------------------------GETS( ) inserted after scanf()**

printf("Email ID :");
scanf("%s",Email);

printf("Contact :");
scanf("%s",contact);

printf("\nYour username is %s\n",username);
printf("Your Email ID is %s\n",Email);
printf("Your Contact No. is %s\n",contact);
printf("Your Address is %s\n",add);

getch();
}

gets() function is not taking any input from the user; once it is used after scanf() function.

1.I don't know why gets function is behaving in this manner?? 2.Same happens with scanf("%c")[format specifier for char] when its is used after scanf("%s")[format specifier of string]

Kaif Bhombal
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    You also really want to read [Why is the gets function so dangerous that it should not be used?](https://stackoverflow.com/questions/1694036/why-is-the-gets-function-so-dangerous-that-it-should-not-be-used) – Retired Ninja Oct 02 '21 at 03:57

1 Answers1

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  1. dont use void main() C++ has never permitted void main(), though some compilers might permit it either as an extension or just because they don't diagnose it.

Similarly C has never permitted void main() other than as an extension; the same 1989 standard that introduced the void keyword.There is no particular advantage in being able to write void main() rather than int main(). You don't even need to explicitly return a value; falling off the end of main is equivalent to return 0; (in C++, and in C starting with C99).

  1. gets()The basic problem is that the function doesn't know how big the buffer is, so it continues reading until it finds a newline or encounters EOF, and may overflow the bounds of the buffer it was given.so,use scanf("%[^\n]s", name); instead of gets(name);.

  2. <conio.h> is a C header file used mostly by MS-DOS compilers to provide console input/output. It is not part of the C standard library or ISO C, nor is it defined by POSIX.so, try use some other compilers.

here is the working version

#include<stdio.h>
#include<string.h>

int main(){

 char username[25],Email[40],contact[15],add[80];
//to be used after   
printf("Enter all your details below\n");


//gets() function does not work after the scanf() function.
//i.e  gets() should be written on top after declaration to work.*

printf("username :");
scanf("%[^\r\n]s",username);
getchar();
printf("Enter your Address:");
scanf("%[^\n]s", add);        

printf("Email ID :");
scanf("%s",Email);

printf("Contact :");
scanf("%s",contact);

printf("\nYour username is '%s'\n",username);
printf("Your Email ID is '%s'\n",Email);
printf("Your Contact No. is '%s'\n",contact);
printf("Your Address is '%s'\n",add);

return 0;
}

the address is taking a newline character from the username statement.so, to print the address properly i used the getchar() function,which detected the newline character before the address taken the input.

vegan_meat
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