c언어 초보 : 대문자 => 소문자

# include <stdio.h>

# include <string.h>

# include <stdlib.h>

int main(void)

{

char Upper_alphabet[] = "HELLO WORLD";

char* Lower_alphabet = NULL;

unsigned int Length = strlen(Upper_alphabet);

int i; // index

Lower_alphabet = (char*)malloc(sizeof(char)*Length);

if (Lower_alphabet == NULL) 

{ 

exit(1);

}

else // Lower_alphabet != NULL

{

//memset(Lower_alphabet, 0, sizeof(char)*Length);

}

printf("strlen(Upper_alphabet) => %d \n", strlen(Upper_alphabet));

for (i = 0; i < Length; i++)

{

int mov = 0;

if (64 <= (int)Upper_alphabet[i] && (int)Upper_alphabet[i] <= 90)

{

mov = (int)Upper_alphabet[i] + 32;

Lower_alphabet[i] = (char)mov;

}

else

// 64 > (int)Upper_alphabet[i] || (int)Upper_alphabet[i] > 90

{

Lower_alphabet[i] = Upper_alphabet[i];

}

}

printf("last(i) => %d \n", i);

Lower_alphabet[i] = '\0';

printf("Upper case [%s] ==> Lower case [%s] \n", Upper_alphabet, Lower_alphabet);

return 0;

}

for문 확인.xlsx