In this tutorial you will learn about the C Strings and its application with practical example.
In C Programming Language a string variable represents sequences of characters that are always enclosed in double-quotes, like “Hello World” ended with a null character (‘\0’). This null character represents the end of the c strings. A string variable can be any length.
In C Programming Language we do not have a string data type like other programming languages, in c we can define a string as an array of characters or a pointer to characters.
<h2>Declaring strings</h2>
<h2>Declaring string as array of characters</h2>
<pre class=”lang:default decode:true”>char s[]=”string”;
OR,
char s[7]=”string”;
OR,
char s[]={‘s’,’t’,’r’,’i’,’n’,’g’,’\0′};
OR;
char s[7]={‘s’,’t’,’r’,’i’,’n’,’g’,’\0′};</pre>
<h2>Declaring string as a pointer to characters sequence</h2>
<pre class=”lang:default decode:true”>char* s = “string”;</pre>
<h2>Example – C program to read string from terminal</h2>
<pre class=”lang:default decode:true”>#include <stdio.h>
int main(){
char name[20];
printf(“Enter your name: “);
scanf(“%s”,name);
printf(“Your name is %s.”,name);
return 0;
}</pre>
<strong>Output:</strong>
<pre class=”lang:default decode:true”>Enter your name: steve
Your name is steve.</pre>
<h2>C String functions</h2>
In C Programming Language we have a rich set of function for string operations like –
<ul>
<li>Counting the length of a string.</li>
<li>Comparing two strings.</li>
<li>Copying one string to another.</li>
<li>Converting lower case string to upper case.</li>
<li>Converting upper case string to lower case.</li>
<li>Joining two strings.</li>
<li>Reversing string.</li>
</ul>
We must have included string.h header file before using these functions.
<table class=”table”>
<tbody>
<tr>
<td><strong> Function</strong></td>
<td><strong> Description</strong></td>
</tr>
<tr>
<td>strcat (str1, str2)</td>
<td> Concatenates str2 at the end of str1.</td>
</tr>
<tr>
<td>strcpy (str1, str 2)</td>
<td> Copies str2 into str1</td>
</tr>
<tr>
<td>strlen (strl)</td>
<td> It returns the length of str1.</td>
</tr>
<tr>
<td>strcmp (str1, str2)</td>
<td> Returns 0 if str1 is same as str2. Returns <0 if strl < str2. Returns >0 if str1 > str2.</td>
</tr>
<tr>
<td>strchr (str1, char)</td>
<td> Returns pointer to first occurrence of char in str1.</td>
</tr>
<tr>
<td>strstr (str1, str2)</td>
<td> Returns pointer to first occurrence of str2 in str1.</td>
</tr>
<tr>
<td>strcmpi (str1, str2)</td>
<td> Same as strcmp() function. But, this function negotiates case. “A” and “a” are treated as same.</td>
</tr>
<tr>
<td>strdup()</td>
<td> duplicates the string</td>
</tr>
<tr>
<td>strlwr()</td>
<td> converts string to lowercase</td>
</tr>
<tr>
<td>strncat()</td>
<td> appends a portion of string to another</td>
</tr>
<tr>
<td>strncpy()</td>
<td> copies given number of characters of one string to another</td>
</tr>
<tr>
<td>strrchr()</td>
<td> last occurrence of given character in a string is found</td>
</tr>
<tr>
<td>strrev()</td>
<td> reverses the given string</td>
</tr>
<tr>
<td>strset()</td>
<td> sets all character in a string to given character</td>
</tr>
<tr>
<td>strupr()</td>
<td> converts string to uppercase</td>
</tr>
<tr>
<td>strtok()</td>
<td> tokenizing given string using delimiter</td>
</tr>
</tbody>
</table>
