User defined String Functions in C

Introduction

Strings are nothing but sequence of characters.

We can store the strings in c using character arrays.

The last character in the character array is always ‘\0’ (null). It marks the end of the string.

Below are some of the different ways of storing the strings in c.

Character arrays declaration

Syntax:

char str[number-of-characters];

char str1[] = "sagar";

char str2[3] = {'a','b','\0'};

char str3[6] = "sagar";

char* str4;

Declaration of string

                Example 1:

        char name[15];

Initializing string

                Example 2:

        char name[15]="Sagar salunke";

Below program will calculate the length of the string.

#include<stdio.h>

void main()

{

      char str[15];

      int i=0;

      printf("\n Enter String : ");

      scanf("%s",str);

      while(str[i]!='\0')

      {

            i++;

     

      }

   printf("\n %s Length is=%d\n",str,i);

   getchar();

}

Below program will reverse the given string.

#include<stdio.h>

void main()

{

      char str[15];

      int i=0,j=0;

      printf("\n Enter String : ");

      scanf("%s",str);

      printf("\n String is :%s\n",str);

      while(str[i]!=NULL)

      {

            i++;

     

      }

      printf("Reverse string is:");

      for(j=i;j>=0;j--)

      {

            printf("%c",str[j]);

      }

   getchar();

}

Below program will count the vowels and consonants in the string.

#include<stdio.h>

void main()

{

  char s1[15];

  int i=0,c1=0,c2=0;

  printf("\n Enter first String : ");

  scanf("%s",s1);

  while(s1[i]!='\0')

   {

      if(s1[i]=='a'||s1[i]=='e'||s1[i]=='i'||s1[i]=='o'||s1[i]=='u')

      {

        c1++;

      }

      else

      {

        c2++;

      }

      i++;

    }

  printf("\n Entered string is :%s",s1);

printf("\n Number of vowels is :%d",c1);

printf("\n Number of consonants is :%d",c2);

   getchar();

}

Below program will convert the upper case string to lower case.

#include<stdio.h>

void main()

{

  char str[15];

  int i=0;

  printf("\n Enter String : ");

  scanf("%s",str);

  printf("\n String is :%s\n",str);

  while(str[i]!='\0')

   {

     if(str[i]>=65 && str[i]<=96)

      {

        str[i]=str[i]+32;

      }

      i++;

   }

   printf("Converted string is:%s",str);

   getchar();

}

Below program will copy one string into another.

#include<stdio.h>

void main()

{

  char s1[15],s2[15];

  int i=0;

  printf("\n Enter first String : ");

  scanf("%s",s1);

  printf("\n Enter second String : ");

  scanf("%s",s2);

  printf("\nBefore copying:");

  printf("\n First string :%s \n Second string :%s",s1,s2);

  for(i=0;i<=14;i++)

   {

     s2[i]=s1[i];

   }

     

   printf("\n After copying:");

   printf("\n First string :%s \n Second string :%s",s1,s2);

   getchar();

}

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