Lab: String Manipulation

1. Program to Count Vowels, Consonants, Digits, and Spaces in a Given String (using scanf)

#include <stdio.h>
#include <ctype.h>

int main() {
    char str[100];
    int vowels = 0, consonants = 0, digits = 0, spaces = 0;

    printf("Enter a string: ");
    scanf("%[^\n]s", str);  // Using %[^\n] to read the whole line including spaces

    for (int i = 0; str[i] != '\0'; i++) {
        char ch = tolower(str[i]);
        if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') {
            vowels++;
        } else if (isalpha(ch)) {
            consonants++;
        } else if (isdigit(ch)) {
            digits++;
        } else if (isspace(ch)) {
            spaces++;
        }
    }

    printf("Vowels: %d\n", vowels);
    printf("Consonants: %d\n", consonants);
    printf("Digits: %d\n", digits);
    printf("Spaces: %d\n", spaces);
    
    return 0;
}

2. Program to Remove All Vowels from a Given String (using scanf)

#include <stdio.h>
#include <ctype.h>

int main() {
    char str[100], result[100];
    int j = 0;

    printf("Enter a string: ");
    scanf("%[^\n]s", str);  // Using %[^\n] to read the whole line including spaces

    for (int i = 0; str[i] != '\0'; i++) {
        char ch = tolower(str[i]);
        if (!(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u')) {
            result[j++] = str[i];
        }
    }
    result[j] = '\0';  // Null terminate the result string

    printf("String without vowels: %s\n", result);

    return 0;
}

3. Program to Check Whether a Given String is a Palindrome

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

int main() {
    char str[100], rev[100];
    int length, flag = 1;

    printf("Enter a string: ");
    scanf("%[^\n]s", str);

    length = strlen(str);
    for (int i = 0; i < length; i++) {
        rev[i] = str[length - i - 1];
    }
    rev[length] = '\0';  // Null terminate the reversed string

    for (int i = 0; i < length; i++) {
        if (tolower(str[i]) != tolower(rev[i])) {
            flag = 0;
            break;
        }
    }

    if (flag)
        printf("The string is a palindrome.\n");
    else
        printf("The string is not a palindrome.\n");

    return 0;
}

4. Program to Convert a Given String to Uppercase Without Using strupr()

#include <stdio.h>
#include <ctype.h>

int main() {
    char str[100];

    printf("Enter a string: ");
    scanf("%[^\n]s", str);

    for (int i = 0; str[i] != '\0'; i++) {
        str[i] = toupper(str[i]);
    }

    printf("Uppercase string: %s\n", str);

    return 0;
}

5. Program to Find the Frequency of Each Character in a String

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

int main() {
    char str[100];
    int freq[256] = {0};  

    printf("Enter a string: ");
    scanf("%[^\n]s", str);

    for (int i = 0; str[i] != '\0'; i++) {
        freq[(unsigned char)str[i]]++;
    }

    printf("Character frequencies:\n");
    for (int i = 0; i < 256; i++) {
        if (freq[i] != 0) {
            printf("%c: %d\n", i, freq[i]);
        }
    }

    return 0;
}