Отправлено: 06.07.17 20:24. Заголовок: How to read a string from the user and concatenate it with a constant string and print it in C?

I want to make a program which reads a sentence entered by the user and combines it with word already declared. For example:
Enter a sentence : is a good day.
The sentence is : Today is a good day.

Here "Today" is the constant string while "is a good day" is the input entered by the user.

 Отправлено: 06.07.17 20:34. Заголовок: There are several ap..

There are several approaches to do the task.

I think that the simplest one is to reserve memory for the prefix "Today" in a character array and then after reading a string to copy this prefix in the beginning of the character array.

Here is a demonstrative program that uses this approach

 
 #include <stdio.h> 
 #include <string.h> 
  
 #define	N	100 
  
 int main(void)  
 { 
 	char s[N]; 
 	char *prefix = "Today "; 
 	const size_t PREFIX_LEN = strlen( prefix ); 
 	 
 	printf( "Enter a sentence: " ); 
 	fgets( s + PREFIX_LEN, N - PREFIX_LEN, stdin ); 
 	memcpy( s, prefix, PREFIX_LEN ); 
 	 
 	s[ strcspn( s, "\n") ] = '\0'; 
 	 
 	printf( "The sentence is: %s\n", s ); 
 	 
 	return 0; 
 }

The program output might look like

 
 Enter a sentence: is a good day.  
 The sentence is: Today is a good day. 
  

Take into account that the function fgets includes the new line character in the array. This statement

 
 s[ strcspn( s, "\n") ] = '\0'; 
 

removes it.

 Отправлено: 07.07.17 18:54. Заголовок: ok thanks for help :..

ok thanks for help :)