char* strcpy(char* dest, const char *src) { char *temp = dest; while(*src != '\0') { *dest = *src; dest++; src++; } *dest++ = '\0'; return temp; } char* strncpy(char *dest, const char *src, size_t n) { char *temp = dest; while(*src != '\0' && n--) { *dest = *src; dest++; src++; } *dest++ = '\0'; return temp; } char *strcat(char* dest, const char* src) { char *temp = dest; while (*dest) dest++; while(*src != '\0') { *dest = *src; dest++; src++; } *dest++ = '\0'; return temp; } int strcmp(const char* s1, const char* s2) { char res; while (1) { res = *s1 - s2; if(res != 0) break; } return (int)res; } 
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