C Programming String
In C programming, array of character are called strings. A string is terminated by null character
/0. For example:"c string tutorial"
Here, "c string tutorial" is a string. When, compiler encounters strings, it appends null character at the end of string.
Declaration of strings
Strings are declared in C in similar manner as arrays. Only difference is that, strings are of
char type.char s[5];
Strings can also be declared using pointer.
char *p
Initialization of strings
In C, string can be initialized in different number of ways.
char c[]="abcd";
OR,
char c[5]="abcd";
OR,
char c[]={'a','b','c','d','\0'};
OR;
char c[5]={'a','b','c','d','\0'};
String can also be initialized using pointers
char *c="abcd";
Reading Strings from user.
Reading words from user.
char c[20];
scanf("%s",c);
String variable c can only take a word. It is beacause when white space is encountered, the
scanf()function terminates.
Write a C program to illustrate how to read string from terminal.
#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.
Here, program will ignore Ritchie because,
scanf() function takes only string before the white space.Reading a line of text
C program to read line of text manually.
#include <stdio.h>
int main(){
char name[30],ch;
int i=0;
printf("Enter name: ");
while(ch!='\n') // terminates if user hit enter
{
ch=getchar();
name[i]=ch;
i++;
}
name[i]='\0'; // inserting null character at end
printf("Name: %s",name);
return 0;
}
This process to take string is tedious. There are predefined functions
gets() and puts in C language to read and display string respectively.int main(){
char name[30];
printf("Enter name: ");
gets(name); //Function to read string from user.
printf("Name: ");
puts(name); //Function to display string.
return 0;
}
Both, the above program has same output below:
Output
Enter name: Tom Hanks Name: Tom Hanks
Passing Strings to Functions
String can be passed to function in similar manner as arrays as, string is also an array. Learn more about passing array to a function.
#include <stdio.h>
void Display(char ch[]);
int main(){
char c[50];
printf("Enter string: ");
gets(c);
Display(c); // Passing string c to function.
return 0;
}
void Display(char ch[]){
printf("String Output: ");
puts(ch);
}
Here, string
c is passed from main() function to user-defined function Display(). In function declaration, ch[] is the formal argument. String handling functions
You can perform different type of string operations manually like: finding length of string, concatenating(joining) two strings etc. But, for programmers ease, many library function are defined under header file
<string.h> to handle these commonly used talk in C programming. You will learn more about string hadling function in next chapter.