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In C programming, character arrays and strings are fundamental concepts that allow you to store and manipulate sequences of characters. Here’s a detailed overview:
Character Arrays
A character array is a sequence of characters stored in contiguous memory locations. In C, a character array can be used to store a string, but it can also store any other characters.
Declaration and Initialization
1. Declaration:
char arrayName[arraySize];
2. Initialization:
- Without specifying the size:
char name[] = {'H', 'e', 'l', 'l', 'o'};
- With size and initialization:
char name[6] = {'H', 'e', 'l', 'l', 'o', '\0'}; // Note the null terminator
String Functions
The C standard library provides a set of functions to manipulate strings. Here are some commonly used functions:
- strlen: Returns the length of the string.
size_t strlen(const char *str);
2. strlen: Returns the length of the string.
char *strcpy(char *dest, const char *src);
3. strncpy: Copies a specified number of characters from one string to another.
char *strncpy(char *dest, const char *src, size_t n);
4. strcat: Concatenates two strings.
char *strcat(char *dest, const char *src);
5. strncat: Concatenates a specified number of characters from one string to another.
char *strncat(char *dest, const char *src, size_t n);
6. strcmp: Compares two strings.
int strcmp(const char *str1, const char *str2);
7. strncmp: Compares a specified number of characters of two strings.
int strncmp(const char *str1, const char *str2, size_t n);
8. strchr: Finds the first occurrence of a character in a string.
char *strchr(const char *str, int c);
9. strrchr: Finds the last occurrence of a character in a string
char *strrchr(const char *str, int c);
10. strstr: Finds the first occurrence of a substring in a string.
char *strstr(const char *haystack, const char *needle);
Examples
- Character Array:
#include <stdio.h>
int main() {
char name[] = {'H', 'e', 'l', 'l', 'o', '\0'};
printf("Name: %s\n", name);
return 0;
}
2. String:
#include <stdio.h>
#include <string.h>
int main() {
char str1[20] = "Hello";
char str2[] = "World";
// Concatenate str2 to str1
strcat(str1, str2);
printf("Concatenated String: %s\n", str1);
printf("Length of String: %lu\n", strlen(str1));
return 0;
}
Memory Considerations
- When using character arrays, ensure that there is enough space to accommodate the string plus the null terminator.
- Strings created using pointers to string literals are read-only. Modifying them can lead to undefined behavior.
Conclusion
Character arrays and strings are vital in C programming for handling text. Proper understanding and use of these constructs, along with string manipulation functions, are essential for efficient and error-free coding.
