Implementation of strcat in C language

1.strcat Introduce

strcat --- String append

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

The source string and destination string must both be in ’\0‘ end ;

The target space must be large enough to be modifiable

2. How to use

strcat Is appended from the destination string ‘\0’ Start adding ; When appending the source string ‘\0’ Will be added to the destination , And the destination ‘\0’ Replaced by the first character of the source string

Error model :

char arr1[] = "hello" ; // arr1 The array space is only 5 Bytes , take world Add the past Is the total 10 Bytes  

                char arr2[] = "world" ;   

                Caused cross-border visits

                char arr1[30] = "hello" ;

                char arr2[] = "world" ; // correct

strcat Cannot self append strings ：strcat（arr1,arr1）// wrong ！

3.strcat The implementation of the

#include<stdio.h>
#include<assert.h>

char* my_strcat(char* destination, const char* source)
{
	{
		char* ret = destination;
		assert(destination && source);
			// Find the destination string '\0'
		while (*destination != '\0')
		{
			destination++;
		}
		// Additional 
		while (*destination++ = *source++)
		{
			;
		}
		return ret;
	}
}


int main()
{
	char arr1[30] = "hello";
	char arr2[] = "world";
	my_strcat(arr1, arr2);
	printf("%s\n", arr1);
	return 0;
}