In C programming, a string is a sequence of characters terminated with a null character \0. For example:
char c[] = "c string";
When the compiler encounters a sequence of characters enclosed in the double quotation marks, it appends a null character \0 at the end by default.
Memory diagram of strings in C programming
How to declare a string?
Here's how you can declare strings:
char s[5];
How to initialize strings?
You can initialize strings in a number of ways.
char c[] = "abcd";
char c[50] = "abcd";
char c[] = {'a', 'b', 'c', 'd', '\0'};
char c[5] = {'a', 'b', 'c', 'd', '\0'};
Initialization of strings in C programming
String Initialization in C
Let's take another example:
char c[5] = "abcde";
Here, we are trying to assign 6 characters (the last character is '\0') to a char array having 5 characters. This is bad and you should never do this.
Assigning Values to Strings
Arrays and strings are second-class citizens in C; they do not support the assignment operator once it is declared. For example,
char c[100];
c = "C programming"; // Error! array type is not assignable.
Note: Use the strcpy() function to copy the string instead.
Read String from the user
You can use the scanf() function to read a string.
The scanf() function reads the sequence of characters until it encounters whitespace (space, newline, tab, etc.).
Example 1: scanf() to read a string
#include <stdio.h>
int main()
{
char name[20];
printf("Enter name: ");
scanf("%s", name);
printf("Your name is %s.", name);
return 0;
}
Output
Enter name: Dennis Ritchie
Your name is Dennis.
Even though Dennis Ritchie was entered in the above program, only "Dennis" was stored in the name string. It's because there was a space after Dennis.
Also notice that we have used the code name instead of &name with scanf().
scanf("%s", name);
This is because name is a charchar
array, and we know that array names decay to pointers in C.
Thus, the name in scanf() already points to the address of the first element in the string, which is why we don't need to use &.
How to read a line of text?
You can use the fgets() function to read a line of string. And, you can use puts() to display the string...
