Difference between revisions of "C-and-C++/C3/Strings/English"

• What is a string.
• Declaration of the string.
• Initialization of the string.
• With the help of an example.

We will aldo see some common errors and their solutions

• Ubuntu Operating System version 11.04
• gcc and g++ Compiler version 4.6.1

String is a sequence of characters that is treated as a single data item

Size of string = length of string + 1

Declaration of the String

Syntax: char val[10];

The syntax for this is

char name_of_string[size];

• char is the data-type
• name_of_string is the string name
• and we can give the size here

Eg- Here we have declared a character string "names" with size 10. Now we will see an example.

example

I have already typed the program.

So I will open it.

Note that our filename is string.c

#include<string.h>

Let me explain the code now.

#include<string.h>

Here, string.h includes the declarations, functions, constants of string handling utilities.

Whenever we work on string functions, we should include this header file.

char strname[30];

printf("Enter the string\n");

scanf("%[^\n]s",strname);

Here we are using the caret sign and \n to include the spaces with the string.

printf("The string is %s\n", strname);

And this is our return statement.

On the terminal

Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard.

gcc strdeclare.c str

>> press Enter

gcc strdeclare.c str

And press Enter.

./str

>> press Enter

./str

and press Enter.

Talk To A Teacher >> press Enter

Talk To A Teacher

Now, press Enter.

Output

The string is Talk To A Teacher

Initialization of the string

Syntax:

char strinitialize[20] = “star”;

(or)

char strinitialize[] = {'S', 't', 'r'};

Until now, we discussed about the declaration of a string.

Now we are going to discuss how to initialize the string.

The syntax for this is

char var_name[size] = “string”;

Eg- Here we have declared a character string "names" with size 10 and the string is "Priya".

Another syntax is char var_name[] = {'S', 't', 'r', 'i', 'n', 'g'};

Eg-char names 10 is equal to Priya within single quotes.

Switch back to the Editor.

We will use the same example.

I CANNOT EDIT THIS SCRIPT ANYMORE. ASHWINI, PLEASE UPDATE THE SCRIPT TO MATCH THE NARRATION OF THE VIDEO ON THE UPLOAD INTERFACE.

File >> Save as option

Type

strinitialize.c

Click on Save as option

Let us save the file with the name strinitialize.c

char name[30] = "Talk To A Teacher";

Let us replace the 5th line with

char strname [30] = “Talk To A Teacher”;

Here we have initialized a character array strname with size '30'

printf("Enter the string\n");

scanf("%[^\n]s",strname);

as we only want to print the string

We are not taking the string as input from the user

Type

gcc strinitialize.c -o str1

Let us compile as before

Type

gcc strinitialize.c -o str1

Type

./str1

Type

./str1

Output

The string is Talk To A Teacher

Type

sting.h

Suppose here we type the spelling of string as

sting

Click on Save

gcc strinitialize.c -o str1

./str1

We see that there is a fatal error

The compiler is not able to find the header file with the name <sting.h>

Hence the compilation is terminated

Come back to the program

Type r here

Let us compile and execute as before

Yes it is working!

Type

int

Suppose I type int here in place of char

Let us see what happens

Come back on the terminal

We see there is an error and a warning

The format specifier for string is %s

And we are declaring it with an integer data type int

Come back to our program

Let us type char here

Let us compile and execute as before

Come back to our program

Save as

Type

.cpp

Click on File menu

Click on Save as option

Now save the file with an extension .cpp

iostream

iostream

#include <string>

Type

#include <string>

using namespace std;

string strname;

Since we don't use the format specifier in C++ ,

the compiler should know that strname is a string variable

cout <<

Type

getline(cin, strname);

Type

getline(cin, strname);

It stores them as a string

cout <<"The string is " <<strname <<"\n";

In place of

printf("The string is %s\n",strname);

Delete the format specifier and \n here

Type two opening angle brackets

Then again type two opening angle brackets here and type within the double quotes \n

Delete the closing bracket here

g++ string.cpp -o str1

g++ string.cpp -o str1

./str1

./str1

I will type Talk To A Teacher

The string is Talk To A Teacher

Assignment

Write a program to print a string using the 2^nd syntax

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