C Programming - C Array of Strings

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C Programming - C Array of Strings

C Array of Strings

An array of strings in C is essentially a two-dimensional array where each row is a string (an array of characters). It is a common way to store multiple strings in a single variable, making it easier to manage and manipulate a group of strings.

1. Declaration and Initialization

Declaration:

To declare an array of strings:

char array_of_strings[row][column];

• row: Number of strings.
• column: Maximum length of each string (including the null character).

Initialization:

(a) Static Initialization:

char names[3][10] = {"Alice", "Bob", "Charlie"};

(b) Dynamic Initialization:

char names[3][10];
strcpy(names[0], "Alice");
strcpy(names[1], "Bob");
strcpy(names[2], "Charlie");

2. Accessing and Modifying Strings

Each string can be accessed using its index:

printf("%s\n", names[0]); // Prints "Alice"
names[1][0] = 'R';        // Modifies "Bob" to "Rob"

3. Input and Output

To take input for an array of strings:

#include <stdio.h>
 
int main() {
    char cities[3][20];
    printf("Enter names of 3 cities:\n");
    for (int i = 0; i < 3; i++) {
        scanf("%s", cities[i]); // Input for each string
    } 
 
    printf("The cities are:\n"); 
    for (int i = 0; i < 3; i++) { 
        printf("%s\n", cities[i]); 
    } 
    return 0; 
}

Output:

Enter names of 3 cities:
London
Paris
Tokyo
The cities are:
London
Paris
Tokyo

4. Passing Array of Strings to a Function

An array of strings can be passed to a function just like any other array.

Example:

#include <stdio.h>

void printStrings(char strings[][20], int n) {
    for (int i = 0; i < n; i++) {
        printf("%s\n", strings[i]);
    }
}

int main() {
    char fruits[3][20] = {"Apple", "Banana", "Cherry"};
    printStrings(fruits, 3);
    return 0;
}

5. Using Pointers for Array of Strings

Instead of a two-dimensional array, an array of pointers to strings can be used:

char *names[] = {"Alice", "Bob", "Charlie"};

Advantages:

• Saves memory since strings of different lengths don't occupy the same fixed space.
• Easier to manage dynamically allocated strings.

Example:

#include <stdio.h>

int main() {
    char *languages[] = {"C", "Python", "Java"};
    for (int i = 0; i < 3; i++) {
        printf("%s\n", languages[i]);
    }
    return 0;
}

6. Example Program: Sorting an Array of Strings

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

int main() {
    char strings[5][20] = {"Banana", "Apple", "Cherry", "Mango", "Grape"};
    char temp[20]; 
 
    // Sorting strings 
    for (int i = 0; i < 5; i++) { 
        for (int j = i + 1; j < 5; j++) { 
            if (strcmp(strings[i], strings[j]) > 0) { // Compare strings 
                strcpy(temp, strings[i]); 
                strcpy(strings[i], strings[j]); 
                strcpy(strings[j], temp); 
            } 
        } 
    } 
 
    printf("Sorted Strings:\n"); 
    for (int i = 0; i < 5; i++) { 
        printf("%s\n", strings[i]); 
    } 
 
    return 0; 
}

Output:

Sorted Strings: 
Apple 
Banana 
Cherry 
Grape 
Mango 

7. Advantages and Limitations

Advantages:

• Simplifies handling multiple strings.
• Allows grouping of related strings (e.g., names, items, etc.).

Limitations:

• Fixed size if declared as a 2D array.
• Managing dynamic memory requires extra care with pointers to avoid memory leaks.

8. Summary

An array of strings is a fundamental concept in C programming that provides an efficient way to handle multiple strings together. Depending on the use case, you can choose between a fixed-size 2D array or a dynamically allocated array of pointers to strings.