Find the count of Alphabetic and Alphanumeric strings from given Array of Strings

In C programming, counting alphabetic and alphanumeric strings from an array involves checking each character in every string. An alphabetic string contains only letters (a-z, A-Z), while an alphanumeric string contains both letters and digits (0-9).

Syntax

int isAlphabetic(char str[]);
int isAlphanumeric(char str[]);
void countStrings(char arr[][MAX_LEN], int n);

Algorithm

The approach to solve this problem involves the following steps

• Step 1 Iterate through each string in the array
• Step 2 Check each character to determine if string is alphabetic or alphanumeric
• Step 3 Count occurrences and maintain frequency of each unique string
• Step 4 Display counts and frequencies

Example 1: Basic Implementation

Here's a complete program to count alphabetic and alphanumeric strings

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

int isAlphabetic(char str[]) {
    for (int i = 0; i < strlen(str); i++) {
        if (!isalpha(str[i])) {
            return 0;
        }
    }
    return 1;
}

int isAlphanumeric(char str[]) {
    int hasDigit = 0, hasAlpha = 0;
    for (int i = 0; i < strlen(str); i++) {
        if (isdigit(str[i])) {
            hasDigit = 1;
        } else if (isalpha(str[i])) {
            hasAlpha = 1;
        } else {
            return 0;
        }
    }
    return hasDigit && hasAlpha;
}

void countStrings(char arr[][50], int n) {
    int alphabeticCount = 0, alphanumericCount = 0;
    
    printf("String analysis:<br>");
    for (int i = 0; i < n; i++) {
        if (isAlphabetic(arr[i])) {
            alphabeticCount++;
            printf(""%s" - Alphabetic<br>", arr[i]);
        } else if (isAlphanumeric(arr[i])) {
            alphanumericCount++;
            printf(""%s" - Alphanumeric<br>", arr[i]);
        } else {
            printf(""%s" - Neither<br>", arr[i]);
        }
    }
    
    printf("\nCounts: %d alphabetic, %d alphanumeric<br>", 
           alphabeticCount, alphanumericCount);
}

int main() {
    char arr[][50] = {"hello", "abc123", "world", "test456", "programming"};
    int n = 5;
    
    printf("Input array: ");
    for (int i = 0; i < n; i++) {
        printf(""%s" ", arr[i]);
    }
    printf("<br><br>");
    
    countStrings(arr, n);
    return 0;
}

Input array: "hello" "abc123" "world" "test456" "programming" 

String analysis:
"hello" - Alphabetic
"abc123" - Alphanumeric
"world" - Alphabetic
"test456" - Alphanumeric
"programming" - Alphabetic

Counts: 3 alphabetic, 2 alphanumeric

Example 2: With Frequency Counting

This example counts frequencies of duplicate strings

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

void countWithFrequency(char arr[][50], int n) {
    int alphabeticCount = 0, alphanumericCount = 0;
    int frequency[50] = {0};
    int processed[50] = {0};
    
    for (int i = 0; i < n; i++) {
        if (processed[i]) continue;
        
        int isAlpha = 1;
        int isAlphanum = 0;
        int hasDigit = 0, hasLetter = 0;
        
        for (int k = 0; k < strlen(arr[i]); k++) {
            if (isdigit(arr[i][k])) {
                hasDigit = 1;
                isAlpha = 0;
            } else if (isalpha(arr[i][k])) {
                hasLetter = 1;
            } else {
                isAlpha = 0;
                hasDigit = hasLetter = 0;
                break;
            }
        }
        
        if (hasDigit && hasLetter) isAlphanum = 1;
        
        frequency[i] = 1;
        for (int j = i + 1; j < n; j++) {
            if (strcmp(arr[i], arr[j]) == 0) {
                frequency[i]++;
                processed[j] = 1;
            }
        }
        
        if (isAlpha) {
            alphabeticCount += frequency[i];
        } else if (isAlphanum) {
            alphanumericCount += frequency[i];
        }
    }
    
    printf("%d %d<br>", alphabeticCount, alphanumericCount);
    
    for (int i = 0; i < n; i++) {
        if (!processed[i] && frequency[i] > 0) {
            printf(""%s": %d<br>", arr[i], frequency[i]);
        }
    }
}

int main() {
    char arr[][50] = {"snmd", "nej7dnr", "snmd", "dltmdj", "lbwm2p6"};
    int n = 5;
    
    countWithFrequency(arr, n);
    return 0;
}

3 2
"snmd": 2
"nej7dnr": 1
"dltmdj": 1
"lbwm2p6": 1

Key Points

• Use isalpha() and isdigit() from ctype.h for character validation
• Alphabetic strings contain only letters (a-z, A-Z)
• Alphanumeric strings contain both letters and digits
• Use strcmp() to find duplicate strings for frequency counting

Conclusion

Counting alphabetic and alphanumeric strings in C involves character-by-character validation using standard library functions. The frequency approach helps identify duplicate strings and their occurrence counts efficiently.