字符串处理

#include <iostream.h>

#include <assert.h>

char* strcat(char* a, const char* b)

{

assert(a != NULL && b != NULL);

char * str = a;

while ( *str++ != '\0' )

NULL;

str--;

while ( (*str++ = *b++ ) != '\0')

NULL;

return str;

}

int strlen(char *p)

{

assert(p != NULL);

if (*p == '\0')

return 0;

else

{

p = p + 1;

return strlen(p) + 1;

}

}

char * strcpy(char * a, const char * b)

{

assert( (a != NULL) && (b != NULL));

char * temp = a;

while ( (*a ++ = *b++) != '\0')

NULL;

return temp;

}

int main(void)

{

char *a = "world";

char b[10]= "hello";

strcat(b, a);

cout<<"b ="<<b<<endl;

return 0;

}