String functions

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strncpy()

strncat()

strstr()

strlen()

—Predefined function defined in string.h .

——Returns the length of string .

—Syntax:  returntype  strlen(string_var_name)

#include<stdio.h>

main()

{

    char ar[20]=“Arvind”;

    printf(“%d”,strlen(ar));

 }

strcmp()

—Used to compare two strings characterwise

——syntax: strcmp(s1,s2)

#include<stdio.h>

#include<string.h>

void main()

{  int i;

  char name[20]=“home";

  char name1[20]="sweet";

  i=strcmp(name,name1);   // name<name1

  printf("%d”,i);

} 

-11

strcpy()

—Defined in string.h

—Used to copy one string to another string

Syntax: strcpy(string1,string2)

Ex

#include<stdio.h>

#include<string.h>

void main()

{   char name1[20];

    char name2[20]=“harry”;

    strcpy(name1,name2);

    printf(“%s”,name1);

 } 

harry

strcat( )

—Also defined in string.h

——Syntax:strcat(string1,string2)

—Append string2 at the end of string1.

Ex.

#include<stdio.h>

#include<string.h>

main( )

{int i;

  char name1[20]="home";

  char name2[20]="sweet";

  strcat(name2,name1);  

  printf("%s",name1);   }

sweethome

Strings

What is string?

—Array of  characters.

—‘\0’ in string signifies end of the string in memory.

—Strings is enclosed within double quotes.

Initializing Strings

—2 ways

—char month1[]={‘j’,’a’,’n’,’u’,’a’,’r’,’y’};

—char month1[]=“january”;

Example

Array of strings

#include<stdio.h>

const int Num=5;

const int length=9;

main()

{

int j;

char Names[Num][length]={“Tejaswi”,”Prasad”,

                                ”Prashant”,”Anand”, “Priya”};

for(j=0;j<Num;j++) printf(“%s\n”,Names[j]);

}

—Output:

   TejaswiPrasad

    Prasanth

    Anand

Input/output

—gets(string) performs input operation .

—puts(string)  performs output operation.

Example

#include<string.h>

#include<stdio.h>

main()

{  char numstr[20];

    puts("enter the string");

   gets(numstr);

    puts(numstr);

}   

—

2D-Array example

/*print Even and Odd no’s among 3x3 matrix/

 #include<stdio.h>

  main( )

{

     int x, i, j, a[i][j], even=0, odd=1;

     for( i=0;i<3; i++ )

      {

          for=0;j<3;j++ )

           {

printf( “enter a no”);

scanf ( “%d”, &a[i][j]);

if( a[i][j]%2== 0 )

          {

             printf( “ even= %d”, a[i][j]  );

            else

               printf( “ odd= %d”,a[i][j] );

             }

 }