String

Overview

This API provides basic string manipulation functions, similar to those found in the C standard library.

• String_Strcat: Concatenates two strings.
• String_Strchr: Finds the first occurrence of a character in a string.
• String_Strcmp: Compares two strings.
• String_Strcpy: Copies a string.
• String_Strlen: Returns the length of a string.

Methods

String_Strcat

Concatenates the source string to the destination string.

char *String_Strcat(char *dest, const char *src);

• Parameters:
  • dest: The destination string. Must have enough space for the result.
  • src: The source string.
• Returns: A pointer to the destination string.

Example:

char dest[50] = "Hello, ";
char src[] = "World!";
String_Strcat(dest, src);
// dest now contains "Hello, World!"

String_Strchr

Finds the first occurrence of a character in a string.

const char *String_Strchr(const char *str, char c);

• Parameters:
  • str: The string to search.
  • c: The character to find.
• Returns: A pointer to the first occurrence of the character, or NULL if not found.

Example:

const char str[] = "Hello, World!";
char c = 'W';
const char *p = String_Strchr(str, c);
// p points to the "W" in "World!"

String_Strcmp

Compares two strings lexicographically.

int String_Strcmp(const char *str1, const char *str2);

• Parameters:
  • str1: The first string.
  • str2: The second string.
• Returns: An integer that is less than, equal to, or greater than zero if str1 is found, respectively, to be less than, to match, or be greater than str2.

Example:

const char str1[] = "Hello";
const char str2[] = "World";
int result = String_Strcmp(str1, str2);
// result is negative because "Hello" comes before "World" alphabetically.

String_Strcpy

Copies the source string to the destination string.

char *String_Strcpy(char *destination, const char *source);

• Parameters:
  • destination: The destination buffer. Must be large enough to hold the source string.
  • source: The source string.
• Returns: A pointer to the destination string.

Example:

char dest[50];
const char src[] = "Hello, World!";
String_Strcpy(dest, src);
// dest now contains "Hello, World!"

String_Strlen

Returns the length of a string.

unsigned int String_Strlen(const char *str);

• Parameters:
  • str: The string to measure.
• Returns: The length of the string, excluding the null terminator.

Example:

const char str[] = "Hello, World!";
unsigned int length = String_Strlen(str);
// length is 13

Usage

Concatenating Strings

#include <appdef.h>
#include <sdk/os/string.h>
#include <sdk/os/debug.h>
#include <sdk/os/lcd.h>

int main() {
    char dest[50] = "Hello, ";
    const char *src = "World!";

    String_Strcat(dest, src);

    Debug_Printf(0, 0, false, 0, "%s", dest); // Output: Hello, World!

    LCD_Refresh();
    Debug_WaitKey();
    return 0;
}

Finding a Character in a String

#include <appdef.h>
#include <sdk/os/string.h>
#include <sdk/os/debug.h>
#include <sdk/os/lcd.h>

int main() {
    const char *str = "Hello, World!";
    char c = 'W';

    const char *p = String_Strchr(str, c);
    if (p) {
        Debug_Printf(0, 0, false, 0, "Found: %s", p); // Output: Found: World!
    } else {
        Debug_Printf(0, 0, false, 0, "Character not found");
    }

    LCD_Refresh();
    Debug_WaitKey();
    return 0;
}

Comparing Strings

#include <appdef.h>
#include <sdk/os/string.h>
#include <sdk/os/debug.h>
#include <sdk/os/lcd.h>

int main() {
    const char *str1 = "Apple";
    const char *str2 = "Banana";

    int result = String_Strcmp(str1, str2);
    if (result < 0) {
        Debug_Printf(0, 0, false, 0, "%s is less than %s", str1, str2);
    } else if (result == 0) {
        Debug_Printf(0, 0, false, 0, "Strings are equal");
    } else {
        Debug_Printf(0, 0, false, 0, "%s is greater than %s", str1, str2);
    }

    LCD_Refresh();
    Debug_WaitKey();

    return 0;
}

Copying a String

#include <sdk/os/string.h>
#include <sdk/os/debug.h>
#include <sdk/os/lcd.h>

// Add headers and app definition here ...

int main() {
    char dest[50];
    const char *src = "Hello, World!";

    String_Strcpy(dest, src);
    Debug_Printf(0,0,false,0, "%s\n", dest); // Output: Hello, World!

    LCD_Refresh();

    return 0;
}

Getting the Length of a String

#include <sdk/os/string.h>
#include <sdk/os/debug.h>
#include <sdk/os/lcd.h>

int main() {
    const char *str = "Hello, World!";

    unsigned int length = String_Strlen(str);
    // Use %u for unsigned int
    Debug_Printf(0, 0, false, 0, "Length of string: %u", length); // Output: 13

    LCD_Refresh();
    Debug_WaitKey();
    return 0;
}