#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define STRLEN 100
#define ERR(source) (perror(source),\
fprintf(stderr,"%s:%d\n",__FILE__,__LINE__),\
exit(EXIT_FAILURE))
void usage(char *name)
{
fprintf(stderr, "USAGE: %s\n", name);
exit(EXIT_FAILURE);
}
char * mystrcat(char* s1, const char* s2)
{
int i = 0, j = 0;
while(*(s1+i) != '\0') ++i;
while(*(s2+j) != '\0')
{
*(s1+i+j) = *(s2+j);
++j;
}
*(s1+i+j) = '\0';
return s1;
}
int main(int argc, char **argv)
{
char* s1;
int i = 0;
if (argc != 3)
usage(argv[0]);
if (NULL == (s1 = (char*) malloc((strlen(argv[1])+strlen(argv[2]))*sizeof(char)))) ERR("malloc");
while(*(argv[1]+i) != '\0')
{
*(s1+i) = *(argv[1]+i);
++i;
}
*(s1+i)='\0';
printf("%s\n", mystrcat(s1, argv[2]));
free(s1);
return EXIT_SUCCESS;
}
