#include <stdio.h>

#include <string.h>

#include <conio.h>

char *doichu(char *s)

{

char *a;

int i=0;

while(*(s+i)!='\0')

{

if((*(s+i)>='A')&&(*(s+i)<='Z'))

*(a+i)=*(s+i)+32;

else

*(a+i)=*(s+i);

i++;

}

*(a+i)='\0';

return a;

}

void main()

{

char s[100];

printf("

Nhap xau: ");

printf("

Chuoi sau khi doi sang chu thuong la: %s",doichu(s));

getch();

}