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.String Manipulations In C Programming Using Library Functions
Strings are often needed to be manipulated by programmer according to the need of a problem. All string manipulation can be done manually by the programmer but, this makes programming complex and large. To solve this, the C supports a large number of string handling functions.
There are numerous functions defined in
"string.h"
header file. Few commonly used string handling functions are discussed below:Function | Work of Function |
---|---|
strlen() | Calculates the length of string |
strcpy() | Copies a string to another string |
strcat() | Concatenates(joins) two strings |
strcmp() | Compares two string |
strlwr() | Converts string to lowercase |
strupr() | Converts string to uppercase |
Strings handling functions are defined under
"string.h"
header file, i.e, you have to include the code below to run string handling functions.#include <string.h>
gets() and puts()
Functions gets() and puts() are two string functions to take string input from user and display string respectively as mentioned in previous chapter.
#include<stdio.h>
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;
}
Though, gets() and
puts()
function handle string, both these functions are defined in "stdio.h"
header file.
here is a bankers algorithm c program for code writing
ReplyDelete