C Programs : Basic Problems And Its Output

C Basics Programs

1.Check a string is a palindrome or not?

Program:-

#include<stdio.h>

#include<string.h>

void isPalindrome(char *str)

{

int i,l,h;

l=strlen(str);

i=0;

h=l-1;

while(h>i)

{

if(str[i++]!=str[h--])

{

printf("Not Palindrome");

return;

}

}

printf("Palindrome");

}

int main()

{

int i,l,flag=0;

char str[20];

printf("Enter a string:-");

scanf("%s",str);

isPalindrome(str);  

 return 0;

}

Output:-

Enter a string:- abcdcba

Palindrome

2.Find the maximum frquency of a character in a string.

Program:-

#include<stdio.h>

#include<string.h>

//#define ASCII_SIZE 256

char string_freq(char *str)

{

int i,j,l,cmax=0,count;

char s;

l=strlen(str);

for(i=0;i<l;i++)

{

count=1;

for(j=i+1;j<l;j++)

{

if(str[i]==str[j])

{

count++;

}

}

if(cmax<count)

{

cmax=count;

s=str[i];

}

}

printf("\n%d",cmax);

return s;

}

int main()

{

char str[20];

printf("Enter a string:-");

scanf("%s",str);

printf("\n%c",string_freq(str));

return 0;

}

3. Remove the duplicate characters from a string.

Program:-

#include<stdio.h>

#include<string.h>

#define ASCII_SIZE 256

void remove_duplicate(char *str)

{

int count[ASCII_SIZE]={0};

int i,j,len;

len=strlen(str);

char b[len];

j=0;

for(i=0;i<len;i++)

{

count[str[i]]++;

if(count[str[i]]==1)

{

b[j]=str[i];

j++;

}

}

printf("Display string:-");

printf("%s",b);

}

int main()

{

char str[20];

printf("Enter a string:-");

scanf("%s",str);

remove_duplicate(str);

return 0;

}

Output:-

Enter string:- programming

poain

4.Find duplicate of a string?

Program:-

#include<stdio.h>

#include<string.h>

void print_duplicate(char *str)

{

int i,len,count,j;

len=strlen(str);

for(i=0;i<len;i++)

{

count=1;

for(j=i+1;j<len;j++)

{

if(str[i]==str[j])

count++;

}

  if(count>=2)

  {

    printf("%c",str[i]);

    printf("%d\n",count);

  }

    }

}

int main()

{

char str[20];

printf("Enter a string:-");

scanf("%s",str);

print_duplicate(str);

  return 0;

}

5. Remove the characters from the first string which common in the second string.

Program:-

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#define ASCII_SIZE 256

 

//Remove characters from string1 which are in string2

char *RemoveChars(char *string1, char *string2)

{

  //Count array stores the count of chars from string2

  int *count = (int *)calloc(sizeof(int), ASCII_SIZE);

  for(int i = 0; *(string2+i);  i++)

  {

      count[*(string2+i)]++;

  }

  int i  = 0, j = 0;

  while(*(string1 + i))

  {

    char temp = *(string1 + i);

    //If count of charcter is zero add to output

    if(count[temp] == 0)

    {

        *(string1 + j) = *(string1 + i);

        j++;

    }

    i++;

  }    

 //Null termination 

  //removing extra characters

  *(string1+j) = '\0';    

 

  return string1;

}

 

int main()

{

char str1[25],str2[20];

printf("Enter the first string:-");

scanf("%s",str1);

printf("\nEnter 2nd string:-");

scanf("%s",str2);

printf("%s",RemoveChars(str1,str2));

return 0;

}