program of string...

String operations

·        Finding length of a string

C program to find string length

#include <stdio.h>

#include <string.h>

int main()

{

   char a[100];

   int length;

   printf("Enter a string to calculate it's length\n");

   gets(a);

    length = strlen(a);

    printf("Length of entered string is = %d\n",length);

    return 0;

}

C program to find string length without strlen

#include<stdio.h>

#include<conio.h>

void main()

{

    char a[50];

    int i,j;

    clrscr();

    printf("\n Please Give The STRING : ");

    scanf("%s",a);

    for(i=0,j=0;a[i]!='\0';i++)

        j++;

    printf("\n THE STRING LENGTH OF %s IS %d .",a,j);

    getch();

}

C program to find length of a string using pointers.

#include <stdio.h>

int main()

{

   char array[100], *pointer;

   int length = 0;

    printf("Enter a string\n");

   gets(array);

    pointer = array;

   while(*(pointer+length))

      length++;

   printf("Length of entered string = %d\n",length);

   return 0;

}

//Function to find string length

int string_length(char *s)

{

   int c = 0;

   while(*(s+c))

      c++;

   return c;

}

·        Converting Characters of a string into upper case and lower case

C program to uppercase the string using strupr().
#include<stdio.h>

//#include<conio.h>

void main()

{

char str[25];

int len;

//clrscr();

printf("Enter the String: ");

gets(str);

strupr(str);

printf("\nYour String in Uppercase %s",str);

}

C program to uppercase the string without using strupr()

#include<stdio.h>

#include<conio.h>

void main()

{

char str[25];

int len,i=0;

printf("Enter the String: ");

gets(str);

while(str[i]!='\0')

{

 if(str[i]>96&&str[i]<123)

 str[i]=str[i]-32;

 i++;

}

printf("\nYour String in Uppercase %s",str);

}

C program to uppercase the string without using strupr() using Pointers.

#include<stdio.h>
void upper(char *);
void main()
{
char str[25];
int len,i=0;
printf("Enter the String: ");
gets(str);
upper(str);

printf("\nYour String in Uppercase %s",str);
}
void upper(char *str1)
{
while(*str1!='\0')
{
 if(*str1>96&&*str1<123)
 *str1=*str1-32;

str1++;
}
}

C program to lowercase the string using strlwr().

#include<stdio.h>

//#include<conio.h>

void main(){

char str[25];

int len;

//clrscr();

printf("Enter the String: ");

gets(str);

strlwr(str);

printf("\nYour String in Lowercase %s",str);

}

C program to lowercase the string without using strlwr().

#include<stdio.h>

#include<conio.h>

void main(){

char str[25];

int len,i=0;

clrscr();

printf("Enter the String: ");

gets(str);

while(str[i]!='\0'){

 if(str[i]<91&&str[i]>64)

 str[i]=str[i]+32;

 i++;

}

printf("\nYour String in Lowerercase %s",str);

}

C program to lowercase the string without using strlwr() using pointers

#include<stdio.h>

#include<conio.h>

void lower(char *);

void main()

{

char str[25];

int len;

clrscr();

printf("Enter the String: ");

gets(str);

lower(str);

printf("\nYour String in Lowercase %s",str);

}

void lower(char *str1)

{

while(*str1!='\0')

{

 if(*str1<91&&*str1>64)

 *str1=*str1+32;

 str1++;

}

}

·        Concatenation of two strings to form a new string

C program to concatenate two strings using strcat().
#include <stdio.h>

#include <string.h>

void main(void)

{

   char str1[25],str2[25],str3[50];

   printf("\nEnter First String:");

   gets(str1);

   printf("\nEnter Second String:");

   gets(str2);

   strcpy(str3,str1);                      

   strcat(str3,str2);                      

   printf("\nConcatenated String is %s",str3);

}

C program to concatenate two strings without using strcat()

#include <stdio.h>

#include <conio.h>

#include <string.h>

void main(){

     char str1[20],str2[20],str3[40]="";

     int len,i,j;

     clrscr();

     printf("Enter string1: ");

     scanf("%s",str1);

     printf("Enter string2: ");

     scanf("%s",str2);

     for(i=0,j=0;str1[i]!='\0';i++,j++)

     str3[j] = str1[i];

     for(i=0;str2[i]!='\0';i++,j++)

     str3[j] = str2[i];

     str3[j] = '\0';

     len = j;

     printf("\n\nAfter Concatination : %s",str3);

     printf("\n\nLength of concated string is %d",len);

     getch();

}

C program to concatenate two strings without using strcat() and using pointers
#include<stdio.h>

void concat(char* ,char* );

void main(void)

{

   char str1[25],str2[25];

   printf("\nEnter First String:");

   gets(str1);

   printf("\nEnter Second String:");

   gets(str2);

   concat(str1,str2);                               

   printf("\nConcatenated String is %s",str1);

}

void concat(char *s1,char *s2)

{

     while(*s1!='\0')                               

             s1++

     while(*s2!='\0')                               

     {

            *s1=*s2;                               

             s1++;                                        

             s2++;                                        

     }

      *s1='\0';                                     

}

·        Reversing a string

C programming code

#include <stdio.h>

#include <string.h>

int main()

{

   char arr[100];

    printf("Enter a string to reverse\n");

   gets(arr);

    strrev(arr);

    printf("Reverse of entered string is \n%s\n",arr);

    return 0;

}

String reverse in c without using string function

#include<stdio.h>

int main(){

char str[50];

char rev[50];

int i=-1,j=0;

printf("Enter any string : ");

scanf("%s",str);

while(str[++i]!='\0');

while(i>=0)

rev[j++] = str[--i];

rev[j]='\0';

printf("Reverse of string is : %s",rev);

return 0;

}

C program to reverse a string using pointers

#include<stdio.h>

int main(){

char str[50];

char rev[50];

char *sptr = str;

char *rptr = rev;

int i=-1;

printf("Enter any string : ");

scanf("%s",str);

while(*sptr){

sptr++;

i++;

}

while(i>=0){

sptr--;

*rptr = *sptr;

rptr++;

--i;

}

*rptr='\0';

printf("Reverse of string is : %s",rev);

return 0;

}

·        Copying a string

C program to copy a string using strcpy

#include<stdio.h>

#include<string.h>

main()

{

   char source[] = "C program";

   char destination[50];

   strcpy(destination, source);

   printf("Source string: %s\n", source);

   printf("Destination string: %s\n", destination);

   return 0;

}

C program to copy a string without strcpy

#include <stdio.h>

int main()

{

char s1[100], s2[100], i;

printf("Enter string s1: ");

scanf("%s",s1);

for(i=0; s1[i]!='\0'; ++i)

{

s2[i]=s1[i];

}

s2[i]='\0';

printf("String s2: %s",s2);

return 0;

}

C program to copy a string using pointers

#include<stdio.h>

void copy_string(char*, char*);

main()

{

    char source[100], target[100];

    printf("Enter source string\n");

    gets(source);

    copy_string(target, source);

    printf("Target string is \"%s\"\n", target);

    return 0;

}

void copy_string(char *target, char *source)

{

   while(*source)

   {

      *target = *source;

      source++;

      target++;

   }

   *target = '\0';

}

·        Comparing strings

C program to compare two strings using strcmp

#include <stdio.h>

#include <string.h>

int main()

{

   char a[100], b[100];

    printf("Enter the first string\n");

   gets(a);

   printf("Enter the second string\n");

   gets(b);

   if( strcmp(a,b) == 0 )

      printf("Entered strings are equal.\n");

   else

      printf("Entered strings are not equal.\n");

   return 0;

}

C program to compare two strings without using string functions

#include<stdio.h>

int stringCompare(char[],char[]);

int main()

{

char str1[100],str2[100];

int compare;

printf("Enter first string: ");

scanf("%s",str1);

printf("Enter second string: ");

scanf("%s",str2);

compare = stringCompare(str1,str2);

if(compare == 1)

printf("Both strings are equal.");

else

printf("Both strings are not equal");

return 0;

}

int stringCompare(char str1[],char str2[]){

int i=0,flag=0;

while(str1[i]!='\0' && str2[i]!='\0'){

if(str1[i]!=str2[i]){

flag=1;

break;

}

i++;

}

if (flag==0 && str1[i]=='\0' && str2[i]=='\0')

return 1;

else

return 0;

}

C program to compare two strings using pointers

#include<stdio.h>

int compare_string(char*, char*);

 int main()

{

    char first[100], second[100], result;

     printf("Enter first string\n");

    gets(first);

    printf("Enter second string\n");

    gets(second);

     result = compare_string(first, second);

     if ( result == 0 )

       printf("Both strings are same.\n");

    else

       printf("Entered strings are not equal.\n");

    return 0;

}

int compare_string(char *first, char *second)

{

   while(*first==*second)

   {

      if ( *first == '\0' || *second == '\0' )

         break;

     first++;

      second++;

   }

   if( *first == '\0' && *second == '\0' )

      return 0;

   else

      return -1;

}

·        Insertion

#include <stdio.h>

#include <conio.h>

#include <string.h>

void main()

{

char a[10];

char b[10];

char c[10];

int p=0,r=0,i=0;

int t=0;

int x,g,s,n,o;

clrscr();

puts("Enter First String:");

gets(a);

puts("Enter Second String:");

gets(b);

printf("Enter the position where the item has to be inserted: ");

scanf("%d",&p);

r = strlen(a);

n = strlen(b);

i=0;    // Copying the input string into another array

while(i <= r)

{

c[i]=a[i];

i++;

}

s = n+r;

o = p+n;    // Adding the sub-string

for(i=p;i<s;i++)

{

x = c[i];

if(t<n)

{

a[i] = b[t];

t=t+1;

}

a[o]=x;

o=o+1;

}

printf("%s", a);

getch();

}

C programming code to Insertion substring using pointer

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

void insert_substring(char*, char*, int);

char* substring(char*, int, int);

int main()

{

   char text[100], substring[100];

   int position;

   printf("Enter some text\n");

   gets(text);

   printf("Enter the string to insert\n");

   gets(substring);

   printf("Enter the position to insert\n");

   scanf("%d", &position);

   insert_substring(text, substring, position);

   printf("%s\n",text);

   return 0;

}

void insert_substring(char *a, char *b, int position)

{

   char *f, *e;

   int length;

   length = strlen(a);

   f = substring(a, 1, position - 1 );     

   e = substring(a, position, length-position+1);

   strcpy(a, "");

   strcat(a, f);

   free(f);

   strcat(a, b);

   strcat(a, e);

   free(e);

}

char *substring(char *string, int position, int length)

{

   char *pointer;

   int c;

   pointer = malloc(length+1);

   if( pointer == NULL )

       exit(EXIT_FAILURE);

   for( c = 0 ; c < length ; c++ )

      *(pointer+c) = *((string+position-1)+c);      

   *(pointer+c) = '\0';

   return pointer;

}

·        Substring

Searching the substring

#include<stdio.h>
#include<conio.h>

void main()
{
            char str[80],search[10];         
            int count1=0,count2=0,i,j,flag;
            clrscr();

           

            puts("Enter a string:");
            gets(str);

            puts("Enter search substring:");
            gets(search);

            while (str[count1]!='\0')
                        count1++;

            while (search[count2]!='\0')
                        count2++;

            for(i=0;i<=count1-count2;i++)
            {
                        for(j=i;j<i+count2;j++)
                        {
                                    flag=1;
                                    if (str[j]!=search[j-i])
                                    {
                                        flag=0;
                                       break;
                                    }
                        }
                        if (flag==1)
                                    break;
            }
            if (flag==1)
                        puts("SEARCH SUCCESSFUL!");
            else
                        puts("SEARCH UNSUCCESSFUL!");
            getch();
}

Extract the substring

First way:
#include<conio.h>
#include<stdio.h>
#include<string.h>
void main()
{
char og[50],ss[50];
int x,y,st,len;
//clrscr();
printf("Enter the String: ");
scanf("%s",og);
printf("Enter the start position and length to be extracted");
scanf("%d%d",&st,&len);
for(x=st,y=0;y<len&&og[x]!='\0';x++,y++) {
ss[y]=og[x];
}
ss[y]='\0';
printf("Your Substring is %s",ss);
getch();
}
Second way: using Pointer's
#include<conio.h>
#include<stdio.h>
#include<string.h>
void extract(char *,char *,int ,int );
void main()
{
char og[50],ss[50];
int x,y,st,len;
//clrscr();
printf("Enter the String: ");
scanf("%s",og);
printf("Enter the start position and length to be extracted");
scanf("%d%d",&st,&len);
extract(og,ss,st,len);
printf("Your Substring is %s",ss);
getch();
}

void extract(char *str1,char *str2,int s,int l)
{
int i;
str1=str1+(s-1);
for(i=0; i < l && str1 != '\0' ;i++)
{
*str2++=*str1++;
}
*str2='\0';
}

·         Deletion

#include<stdio.h>
#include<conio.h>
#include<string.h>

void remove(char[],int,int);
main()
{
char a[80];
int s,e;
clrscr();
printf("Enter a string\n");
gets(a);
printf("Enter start\n");
fflush(stdin);
scanf("%d",&s);
printf("Enter end\n");
scanf("%d",&e);
remove(a,s,e);
getch();
return 0;
}
void remove(char a[],int s,int e)
{
int i;
while(a[i]!='\0')
{
for(i=0;i<s&&a[i];i++)
printf("%c",a[i]);
for(i=s;i<=e&&a[i];i++);
for(;a[i]!='\0';i++)
printf("%c",a[i]);
}
}

Delete substring at given position

#include<conio.h>

#include<stdio.h>

#include<string.h>

void main()

{

      int len1,len2,i,cntr1,cntr2,flag=0;

      char str1[50],str2[50];

      clrscr();

      printf("Enter the main String and the substring to be deleted:\n");

      scanf("%s%s",str1,str2);

      len1=strlen(str1);

      len2=strlen(str2);

      for(i=0;len2<=len1-i;i++)

      {

            for(cntr1=i,cntr2=0;cntr2<=len2&&str1[cntr1]==str2[cntr2];cntr1++,cntr2++);

            if(len2<=cntr2)

            {

                  flag=1;

                  break;

            }

      }

      if(flag==0)

      printf("%s substring is not present in string %s so cannot be deleted",str2,str1);

      else

      {

            for(;(i+len2+1)<=len1;i++)

            str1[i]=str1[len2+i];

            str1[i]='\0';

      }

      printf("\nSubstring %s has been deleted and resultant string is :  %s",str2,str1);

getch();

}

Delete substring using pointer

#include "stdio.h"

#include "conio.h"

#include "string.h"

void delchar(char *x,int a, int b);

void main(){

char string[10];

int n,pos,p;

clrscr();

puts("Enter the string");

gets(string);

printf("Enter the position from where to delete");

scanf("%d",&pos);

printf("Enter the number of characters to be deleted");

scanf("%d",&n);

delchar(string, n,pos);

getch();

}

void delchar(char *x,int a, int b){

if ((a+b-1) <= strlen(x)){

strcpy(&x[b-1],&x[a+b-1]);puts(x);

}

}