12.6 Lab8

introduction-to-computer-science-laboratory-8.pdf

Introduction to Computer Science - Laboratory 8

1. Write a C program that:

   • Takes a word as input from standard input.
   • Determines if it is a palindrome. (A palindrome is a word that reads the same backward and forward, e.g., "racecar").

   #include<stdio.h>
   
   int main() {
       int word[32];
       int ch;
       int letternumber = 0;
       printf("Please type a word in lowercase: ");
       for(int i = 0; ch != EOF; i++) {
           ch = getchar();
           if(ch >= 'a' && ch <= 'z') {
               letternumber++;
               word[i] = ch;
           }
       }
   
       int is_palindrome = 1;
   
       for(int j = 0; j < letternumber; j++) {
           if(word[j] != word[letternumber - j - 1])
               is_palindrome = 0;
       }
   
       if(is_palindrome == 1) {
           printf("Yes, ");
           for(int k = 0; k < letternumber; k++) {
               printf("%c", word[k]);
           }
           printf(" is a palindrome!!!\n");
       }
       else {
           printf("No, ");
           for(int l = 0; l < letternumber; l++) {
               printf("%c", word[l]);
           }
           printf(" is not a palindrome!!!\n");
       }
       return 0;
   }
   

2. Write a C program that:

   • Receives as input a number N​ and a sequence of M​ elements (where M >= N​).
   • Calculates the Nth smallest number in the sequence.

   #include<stdio.h>
   
   int main() {
       int n, m;
       int lowlimit = 0;
       int lowposition = 0;
   
       printf("Please enter a number n and a number m:");
       scanf("%d %d", &n, &m);
       int sequence[m];
       // store the sequence
       printf("Please enter a sequence:");
       for (int i = 0; i < m; i++) {
           scanf("%d", &sequence[i]);
       }
   
       //find Nth smallest number
       while(lowlimit < n) {
           lowposition = lowlimit;
           for(int j = lowlimit; j < m; j++) {
               if(sequence[j] < sequence[lowposition]) {
                   lowposition = j;
               }
           }
           //swap the smaller element to the front
           int temp;
           temp = sequence[lowlimit];
           sequence[lowlimit] = sequence[lowposition];
           sequence[lowposition] = temp;
   
           lowlimit++;
       }
       printf("%d", sequence[lowlimit - 1]);
       return 0;
   }
   

3. Write a program that:

   • Takes a sequence of integer numbers and an integer number N​ as input.
   • If N​ is in the sequence, prints N​’s position; otherwise, prints -1​.

   #include<stdio.h>
   
   int main() {
       int N, number_sequence;
       printf("Please enter a number N and the number of sequence: ");
       scanf("%d %d", &N, &number_sequence);
       int sequence[number_sequence];
   
       // store the sequence
       printf("Please enter a sequence:");
       for (int i = 0; i < number_sequence; i++) {
           scanf("%d", &sequence[i]);
       }
   
       //record the flag and position if the number is in the sequence
       int is_same = 0;
       int is_same_position;
   
       //compare the value
       for(int j = 0; j < number_sequence; j++) {
           if(sequence[j] == N) {
               is_same = 1;
               is_same_position = j + 1;
           }
       }
   
       //output
       if(is_same == 1)
           printf("Yes, %d is in the sequence and it's position is %d", N, is_same_position);
       else
           printf("-1");
   }
   

4. Write a C program that:

   • Takes a sequence of integer numbers as input.
   • Classifies the sequence into even and odd numbers.
   • Prints the even numbers first, followed by the odd numbers.

   #include<stdio.h>
   
   int main() {
       int number_sequence;
       printf("Please enter the number of sequence: ");
       scanf("%d", &number_sequence);
   
       //define two arraies to store the number
       int evenseq[number_sequence];
       int oddseq[number_sequence];
       int inputnumber;
   
       //store the sequence
       printf("Please enter a sequence:");
       int i = 0;
       int j = 0;
       // seperate the even numbers and odd numbers into two array
       while((i + j) < number_sequence) {
           scanf("%d", &inputnumber);
           if(inputnumber % 2 == 0) {
               evenseq[i] = inputnumber;
               i++;
           }
           else {
               oddseq[j] = inputnumber;
               j++;
           }
       }
   
       for(int k = 0; k < i; k++) 
           printf("%d", evenseq[k]); //warning!!! usual mistake!!! donot write evenseq[i]
   
       for(int k = 0; k < j; k++) 
           printf("%d", oddseq[k]);
   
       return 0;
   }
   

5. Design and implement a C program that:

   • Takes an integer number K​ and a sequence of integer numbers as input.
   • Counts all the numbers in the sequence greater than K​.

   #include<stdio.h>
   
   int main() {
       int K, number_sequence;
       printf("Please enter a number K and the number of sequence: ");
       scanf("%d %d", &K, &number_sequence);
       int sequence[number_sequence];
   
       // store the sequence
       printf("Please enter a sequence:");
       for (int i = 0; i < number_sequence; i++) {
           scanf("%d", &sequence[i]);
       }
   
       int times = 0;
       for(int i = 0; i < number_sequence; i++) {
           if(sequence[i] > K)
               times++;
       }
       printf("The number of number which is greater than K is %d", times);
       return 0;
   }