-     #include <stdio.h> 
-     #include <stdlib.h> //for malloc 
-     #include <string.h> 
-   
-     int *my_strcat(const char* const str1, const char *const str2) 
-     { 
-     	int s1, s2, s3, i=0; 
-     	char *a; 
-     	s3 = s1+s2+1; 
-     	for(i = 0; i < s1; i++) { 
-     		a[i] = str1[i]; 
-     	} 
-     	for(i = 0; i < s2; i++) { 
-     		a[i+s1] = str2[i]; 
-     	} 
-     	a[s3] = '\0';   
-   
-     	return a; 
-     } 
-   
-   
-     int main(void) 
-     { 
-     	printf("%s\n",- my_strcat ("Hello","world!"));
 
-     	return 0;     
-     } 
-   
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