How to use str in c language

The str function is a commonly used string processing function in C language. It is used to perform various operations, including: concatenating strings (strcat) comparing strings (strcmp) copying strings (strcpy) and calculating string length. (strlen)

Usage of str in C language

Introduction:
str is one of the most commonly used string processing functions in C language. It allows manipulating null-terminated character arrays (strings) and performing various operations.

Syntax:

char *str(const char *str1, const char *str2);

Parameters:

• str1: The operation to be performed The first string.
• str2: The second string to perform the operation on.

Return value:
Returns a pointer to the result string.

Usage:
The str function can be used for various string operations, including:

• String concatenation (strcat): Append str2 to the end of str1.
• String comparison (strcmp): Compares str1 and str2, returning 0 (equal), a positive integer (str1 is greater than str2), or a negative integer (str1 is less than str2).
• String copy (strcpy): Copy str2 to str1, overwriting the existing content in str1.
• String length (strlen): Returns the number of characters in str1 (not including the null terminator).

Example:

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

int main() {
    char str1[] = "Hello";
    char str2[] = "World";

    // 字符串连接
    strcat(str1, " ");
    strcat(str1, str2);
    printf("连接后的字符串：%s\n", str1);

    // 字符串比较
    int result = strcmp(str1, "Hello World");
    if (result == 0) {
        printf("字符串相等\n");
    } else if (result > 0) {
        printf("str1 大于 str2\n");
    } else {
        printf("str1 小于 str2\n");
    }

    // 字符串复制
    strcpy(str1, str2);
    printf("复制后的字符串：%s\n", str1);

    // 字符串长度
    int length = strlen(str1);
    printf("字符串长度：%d\n", length);

    return 0;
}

Output:

<code>连接后的字符串：Hello World
字符串相等
复制后的字符串：World
字符串长度：5</code>

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