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String Functions in C

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<b><br /></b>
<b>String Function:</b><br />
<b><br /></b>
The standard library for C string functions is string.h. This header file defines tons of useful string manipulation functions including:<br />
<ul style="text-align: left;">
<li>strcmp</li>
<li>strcat</li>
<li>strcpy</li>
<li>strlen</li>
</ul>
<div>
<b>strcmp:</b></div>
<div>
strcmp() in C programming language is used to compare two string. If both the strings are equal then it gives the result as zero but if not then it gives the numeric difference between the first non matching character in the string.</div>
<div>
<br /></div>
<div>
<b>Syntax:</b><br />
<b><br /></b></div>
<div>
<pre class="_codebox">int strcmp(const char *str1, const char *str2);
</pre>
<br /></div>
<div>
<b>Example:</b><br />
<b><br /></b></div>
<div>
<pre class="c" name="code">int main()
{
   char str1[30], str2[30];
   printf("Enter first string : ");
   scanf("%s", &str1);
   printf("Enter second string : ");
   scanf("%s", &str2);
   if(strcmp(str1, str2)==0))
      printf("Both strings are equal.")
   else
      printf("strings are not equal.");
   return 0;
}</pre>
<br /></div>
<div>
<b>Output:</b><br />
<b><br /></b>
<br />
<pre class="_codebox">Enter first string : studycodemaster
Enter second string : studycodemaster
Both strings are equal.
</pre>
<b><br /></b>
<b>strcat:</b></div>
<div>
The strcat() function is used for string concatenation in C programming language. Which means this function is used to join the two string together.<br />
<br /></div>
<div>
<b>Syntax:</b><br />
<br /></div>
<pre class="_codebox">strcat(string1, string2);
</pre>
<div>
<br />
<b>Example:</b></div>
<br />
<pre class="c" name="code">int main()
{
   char string1[50]="www.studycodemaster";
   char string2[5]=".blogspot.com";
   printf("Before concatenation the strings are : ");
   printf("\nstring1 : %s", string1);
   printf("\nstring2 : %s", string2);
   printf("\nAfter concatenation the string is : ")
   printf("string : %s", strcat(string1, string2));
   return 0;
}</pre>
<br />
<div>
<b>Output:</b><br />
<b><br /></b>
<br />
<pre class="_codebox">Before concatenation the strings are :
string1 : www.studycodemaster
string2 : .blogspot.com
After concatenation the string is :
string : www.studycodemaster.blogspot.com
</pre>
<b><br /></b>
<b>strcpy:</b></div>
<div>
strcpy() function is used to copies a string from a source location to a destination location and provides a null character to terminate the string.</div>
<br />
<div>
<b>Syntax:</b><br />
<b><br /></b></div>
<div>
<div>
<pre class="_codebox">strcpy(destination, source);
</pre>
<br /></div>
<div>
<b>Example:</b><br />
<b><br /></b></div>
</div>
<div>
<pre class="c" name="code">int main()
{
   char string1[50], string2[50];
   printf("Enter string : ");
   scanf("%s", &string1);
   strcpy(string2, string1);
   printf("string1 : %s ", string1);
   printf("string2 : "%s , string2);
   return 0;
}</pre>
</div>
<br />
<div>
<b>Output:</b><br />
<b><br /></b>
<br />
<pre class="_codebox">Enter string : www.studycodemaster.blogspot.com
string1 : www.studycodemaster.blogspot.com
string2 : www.studycodemaster.blogspot.com
</pre>
<b><br /></b>
<b>strlen:</b></div>
<div>
The strlen() is used to calculate the length of the string. Which means strlen function counts the total number of characters present in the string which includes alphabets, numbers, and all special characters including blank spaces.</div>
<br />
<div>
<b>Syntax:</b><br />
<b><br /></b></div>
<div>
<div>
<pre class="_codebox">count = strlen(stringvariable);
</pre>
<br /></div>
<div>
<b>Example:</b><br />
<b><br /></b></div>
</div>
<div>
<pre class="c" name="code">int main()
{
   char str[20];
   printf("Enter a string : ");
   scanf("%s", &str);
   printf("Length of the string is : %d", strlen(str));
   return 0;
}
</pre>
<br />
<b>Output:</b><br />
<br />
<pre class="_code">Enter a string : www.studycodemaster.blogspot.com
Length of the string is : 32
</pre>
</div>
</div>

String Functions in C

String Function: The standard library for C string functions is string.h. This header file defines tons of useful string manipulatio...

Program to copy the contents of one file into another using fgetc and fputc function

void main()
{
   FILE *fp1,*fp2;
   char a;
   clrscr();

fp1=fopen("test.txt","r");
   if(fp1==NULL)
   {
      puts("cannot open this file");
      exit(1);
   }

fp2=fopen("test1.txt","w");
   if(fp2==NULL)
   {
      puts("Not able to open this file");
      fclose(fp1);
      exit(1);
   }

do
   {
      a=fgetc(fp1);
      fputc(a,fp2);
   }while(a!=EOF);

fcloseall();
   getch();
}
</pre>
<br />
<b>Output:</b><br />
<pre class="_codebox">Content will be written successfully to file
</pre>
<br />
<b>Explanation of Program :</b><br />
<br />
We have to files with us , we are opening one file in read mode and another file in write mode.<br />
<pre class="_codebox">fp1=fopen("test.txt","r");
</pre>
<br />
and<br />
<pre class="_codebox">fp2=fopen("test1.txt","w");
</pre>
<br />
<br />
It is better practice to check whether file is opened successfully or not using NULL check.<br />
<br />
<pre class="_codebox">if(fp2==NULL)
{
   //File is Not opened Successfully

}
</pre>
<br />
If everything goes right then we are reading file character by character and writing on file character by character.<br />
<pre class="_codebox">a=fgetc(fp1); //Reading Single Character
</pre>
<br />
End of File is specified by EOF character, thus if we get EOF character then process of writing on the file will be terminated.<br />
<br />
<pre class="_codebox">do
{
   a=fgetc(fp1);
   fputc(a,fp2);
}while(a!=EOF);
</pre>
</div>

Program to copy the contents of one file into another using fgetc and fputc function

#include<stdio.h> #include<process.h> void main() { FILE *fp1,*fp2; char a; clrscr(); fp1=fopen("test.tx...

Functions in C language

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<br /></div>
<div style="text-align: justify;">
<b><u>What is function, Types of functions and example of functions.</u></b><br />
<b><u><br /></u></b>
In simple word function is a self-contained sub-program that are designed to perform some specific task. Any C program contain more than one functions. If there exist only one function in a C program then it must be main(). main() is a function from where every C program have to be start or we can say it is the initial point from where every program have to be started.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
If a C program contain functions (excluded main function) then that functions can be called directly or indirectly from the main().</div>
<div style="text-align: justify;">
<br />
Whenever a call or create a function we pass some values to that function and that function perform their specific task and it returns back some value to the main() function.<br />
<br /></div>
<div style="text-align: justify;">
<b><u>Advantages of using Functions</u></b></div>
<div style="text-align: justify;">
<span style="font-weight: bold;"><br /></span></div>
<div style="text-align: justify;">
A function has following advantages</div>
<ol style="text-align: left;">
<li style="text-align: justify;">A large program can be divided into sub-programs and sub-programs easily understandable. A program can be divided into functions, each of which perform some specific task. thus the function is used to divides the work of a program.</li>
<li style="text-align: justify;">As I said sub-programs easily understandable so that's why it is easily modified and easy to debug and tested. It becomes simple to write the program and understand what task is completed by each part of the program.</li>
<li style="text-align: justify;">Function follow the rule of Abstraction because whenever we create a function the details of how the work is done is hidden inside the function body.</li>
<li style="text-align: justify;">Functions can be stored in a library and can be reused.</li>
</ol>
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<div style="text-align: justify;">
<br /></div>
</div>
<div>
<div style="text-align: justify;">
<b><u>Types of Functions</u></b></div>
</div>
<div>
<div style="text-align: justify;">
<b><br /></b></div>
</div>
<div>
<div style="text-align: justify;">
C program have two types of function.</div>
</div>
<div>
<ol style="text-align: left;">
<li style="text-align: justify;">Library functions.</li>
<li style="text-align: justify;">User-defined functions.</li>
</ol>
<div>
<div style="text-align: justify;">
<b><u>Library Functions</u></b></div>
</div>
</div>
<div>
<div style="text-align: justify;">
<br /></div>
</div>
<div>
<div style="text-align: justify;">
C program has a service or we can say facility which provide library functions for doing some operations like scanf(), printf() etc. these functions  are presented in the C library and they are predefined which means we can not modify or delete that functions. therefore to use the library function in our C program we have to include to corresponding header file using the preprocessor directive  that is #include.</div>
</div>
<div>
<div style="text-align: justify;">
For example if we want to use printf() function then we have to include the header file #include<stdio.h></div>
</div>
<div>
<div style="text-align: justify;">
<br /></div>
</div>
<div>
<div style="text-align: justify;">
<b><u>A simple program using library function</u></b></div>
</div>
<div>
<div style="text-align: justify;">
<br /></div>
</div>
<div>
<div style="text-align: justify;">
Program: Write a program to find the square root of a number?</div>
</div>
<div>
<div style="text-align: justify;">
<br /></div>
</div>
<div>
<pre class="c" name="code">#include<stdio.h>
#include<math.h>
int main(void)
{
    double num, sqrroot;
    printf("Enter a number : ");
    scanf("%lf", &num);
    sqrroot=sqrt(num);
    printf("Square root of %.2lf is %2lf\n", num, sqrroot");
    return 0;
}
</pre>
</div>
<div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<b><u>Output</u></b></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
Enter a number : 16</div>
<div style="text-align: justify;">
Square root of 16.00 is 4.00</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
Ok in this program we have used basically three functions that are Library Function.</div>
<div style="text-align: left;">
</div>
<ol style="text-align: left;">
<li style="text-align: justify;">printf();</li>
<li style="text-align: justify;">scanf();</li>
<li style="text-align: justify;">sqrt();</li>
</ol>
<div>
<div style="text-align: justify;">
<b><u>User-Defined Functions</u></b><br />
<b><u><br /></u></b>
In a C program a programmer create a function to perform some specific task is called user-defined functions. User-defined functions has no type that are task specific which can be modified by the programmer.<br />
For example if we need to calculate the sum of two number more than times them we can create a function which perform addition of two number several times in program hence creating a function is useful because it save our time space and it is also easy to understand whenever we need to perform addition of two number then we have to just call it and left the addition action on that function. When a function is called sometimes it takes some value that is arguments and returns the result to the calling function.<br />
Lets check a simple demonstration of an user-defined function<br />
<br />
Program: Write a program to find out sum of two numbers.<br />
<br />
<pre class="c" name="code">#include<stdio.h>
int main(void)
{
    double num1, num2, sum;
    printf("Enter any two numbers : ");
    scanf("%d%d", &num1, &num2);
    sum=addtion(num1, num2);  //Function call
    printf("Sum of %d and %d is : %d", num1, num2, sum);
    return 0;
}

int addtion(int a, int b)  //Function body or Function definition
{
    int sum;
    sum = a+b;
    return sum;  //Return the sum
}
</pre>
<br />
<b><u>Output</u></b><br />
<b><u><br /></u></b>
Enter any two number : 10  20<br />
Sum of 10 and 20 is : 30<br />
<br />
<b><u>Function Definition</u></b><br />
<b><u><br /></u></b>
Function definition contain the whole code and description of a function. It describe the whole functionality of the function, what task is to be done by the function which parameters it has to be take and what type of result it will returns to the calling function.<br />
Normally a function definition is combined into two parts<br />
<br />
<ol>
<li>A function header.</li>
<li>Function body.</li>
</ol>
<div>
Following is the general syntax of function.</div>
<div>
<pre class="c" name="code">return_type func_name(parameters declaration)
{
    local variable declaration;
    statements;
    --------------------------
    --------------------------
    return (expression);
}
</pre>
<br />
In above code the first line is known as <b>function header</b>, after function header next whole part is <b>function body</b> which is written enclosed in curly braces.<br />
<br />
The return_type means the type of value which will be returned by the function. A function can return either one value or no value. If the return type of function is no value means if a function that does not return any value then void should be written in place of return type. If no return type specified in the definition then int return type is assumed.<br />
<br />
func_name specify the name of the function and it can be any valid C identifier. After the function name a comma separated list of parameters declaration is given inside parentheses which define the type and name of the parameter.These parameters are also called formal parameters and used to accept the values from the calling function.A function can have any number of parameters even no parameters at all.<br />
<br />
The body of function is a block which consist of declarations of variables, and C statements followed by additional optional return statement. The variable which are declared inside the function is known as local variables which means the existence of that variable is only for that function. Local variable can not be accessed directly outside the function.<br />
<br />
The function definition can be placed anywhere in the program or function definition can also be placed in different source file. But generally all definitions are placed after the main() function. A function definition can not be placed inside any function. </div>
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Functions in C language

What is function, Types of functions and example of functions. In simple word function is a self-contained sub-program that are ...

C language Overview and first Program in c to print Hello World

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<br /></div>
<div style="text-align: justify;">
As we know that C is a <b>high-level language</b> or we can say <b>general-purpose langauge</b> that was developed by Dennis M. Ritchie to develop the UNIX operating system at Belle Labs.</div>
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<br /></div>
<div style="text-align: justify;">
Originally C was first implemented on the Dec PDP-11 computer in 1972.</div>
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The UNIX operating system, the C compiler and all UNIX program were written in C Language. Hence therefore C language has now become a widely used professional language.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<b>Why it is widely used professional language there are some aspects like</b></div>
<ul style="text-align: left;">
<li style="text-align: justify;">Easy to learn.</li>
<li style="text-align: justify;">structured language.</li>
<li style="text-align: justify;">it produce effective and efficient programs</li>
<li style="text-align: justify;">it can handle low level activities</li>
<li style="text-align: justify;">and most impotant thing is it can compiled on a varietyof computer platform.</li>
</ul>
<div>
<div style="text-align: justify;">
<u><b>First program in C to print <b>HELLO WORLD</b></b></u></div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
//A simple program to print Hello World</div>
<pre name="code" class="c">
#include<stdio.h>
#include<conio.h>
void main()
{
   printf("Print Hello");
   getch();
}
</pre>
<div style="text-align: justify;">
<br /></div>
<div>
<u><b>
</b></u>
</div>
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C language Overview and first Program in c to print Hello World

As we know that C is a high-level language or we can say general-purpose langauge that was developed by Dennis M. Ritchie to develop...

Study Code Master | ASP.NET, C#, VB, PHP, JavaScript, JQuery, HTML 5, Database, MySql, MS-Server

String Functions in C

Program to copy the contents of one file into another using fgetc and fputc function

Functions in C language

C language Overview and first Program in c to print Hello World

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