String Built-in functions

Program:

#include<stdio.h>
#include<string.h>
int main()
{
int i;
char str1[40]="COMPUTER";
char str2[40]="computer";
/*length of string*/
printf("Length of the string %s : %d \n\n",str1,strlen(str1));

/*Compare two strings*/
i=strcmp(str1,str2);
if(i==0)
{
printf("Two Strings are equal\n\n");
}
else
{
printf("Two Strings are not equal\n\n");
}

/*Reverse string*/
printf("reverse of %s is ",str1);
strrev(str1);
printf(" = %s \n\n",str1);

/*Concate string*/
strrev(str1);
printf("concate of %s and %s is ",str1,str2);
strcat(str1,str2);
printf(" = %s \n",str1);

return 0;
}

Output:

Character with ASCII value from a string

Program:

#include<stdio.h>
int main()
{
char str[30];
int i;
printf("Enter a string:\n");
gets(str);
for(i=0;str[i]!='\0';i++)
{
  printf("%c\t%d\n",str[i],str[i]);
}
return 0;
}

Output:

Word count

Program:

#include<stdio.h>
int main()
{
char str[30];
int len=0,i,s=1;
printf("Enter a string:\n");
gets(str);
for(i=0;str[len]!='\0';i++)
{
  if(str[len]==' ')
  s++;
  len++;
}
printf("Total Words: %d",s);
return 0;
}

Output:

Frequency of character

Program:

#include <stdio.h>
int main()
{
   char str[300], ch;
   int i, frequency = 0;
   printf("Enter a string: ");
   gets(str);
   printf("Enter a character to find the frequency: ");
   scanf("%c",&ch);
   for(i=0;str[i]!='\0';i++)
   {
       if(ch==str[i])
        {
          frequency++;
}
   }
   printf("Frequency of %c = %d", ch, frequency);
   return 0;
}

Output:

Palindrome string

Program:

#include<stdio.h>
#include<string.h>
int main()
{
char str[30];
int i,j,flag=0;
printf("Enter a string: ");
scanf("%s",str);
for(i=0,j=strlen(str)-1;i<strlen(str)/2;i++,j--)
{
   if(str[i]!=str[j])
   {
      flag=1;
  break;
   }
}
if(flag==0)
{
printf("Palindrome");
}
else
{
printf(" Not Palindrome");
}
return 0;
}

Output:

String copy

Program:

#include<stdio.h>
int main()
{
char s1[20],s2[20];
int len=0,i;
printf("Enter String: ");
scanf("%s",s1);
while(s1[len]!='\0')
{
len++;
}
for(i=0;i<=len;i++)
{
s2[i]=s1[i];
}
printf("String s2: %s",s2);
return 0;
}

Output:

Concate string

Program:

#include<stdio.h>
int main()
{
char s1[50],s2[30];
int len1,len2,i,j;
printf("Enter first string: ");
scanf("%s",s1);
printf("Enter second string: ");
scanf("%s",s2);
len1=0,len2=0;
while(s1[len1]!='\0')
{
len1++;
}
while(s2[len2]!='\0')
{
len2++;
}
for(j=0,i=len1;j<=len2;i++,j++)
{
s1[i]=s2[j];
}
printf("After Concatenation : %s",s1);
return 0;
}

Output:

Convert into lower string

Program:

#include<stdio.h>
int main()
{
char s1[30],s2[30];
int i=0;
printf("Enter a string: ");
scanf("%s",s1);
while(s1[i]!='\0')
{
if(s1[i]>=65 && s1[i]<=90)
{
s2[i]=s1[i]+32;
}
else
{
s2[i]=s1[i];
}
i++;
}
    s2[i]='\0';
    printf("Lower case string: %s",s2);
return 0;
}


Output:

Convert into upper string

Program:

#include<stdio.h>
int main()
{
char s1[30],s2[30];
int i=0;
printf("Enter a string: ");
scanf("%s",s1);
while(s1[i]!='\0')
{
if(s1[i]>=97 && s1[i]<=122)
{
s2[i]=s1[i]-32;
}
else
{
s2[i]=s1[i];
}
i++;
}
    s2[i]='\0';
    printf("Upper case string: %s",s2);
return 0;
}

Output:

Reverse string

Program:

#include<stdio.h>
int main()
{
char s1[20],s2[20];
int len=0,i,j;
printf("Enter String: ");
scanf("%s",s1);
while(s1[len]!='\0')
{
len++;
}
for(i=0,j=len-1;i<len;i++,j--)
{
s2[j]=s1[i];
}
s2[len]='\0';
printf("Reverse String: %s",s2);
return 0;
}

Output:

Length of string

Program:

#include<stdio.h>
int main()
{
char str[30];
int len=0,i;
printf("Enter a string: ");
gets(str);
for(i=0;str[i]!='\0';i++)
{
  len++;
}
printf("Length of string: %d",len);
return 0;
}

Output: