Write a program to count the number of letters from A-Z in given input

#include

main() {

int c; /* store input char */
int nletters[26]; /*array of 26 cells */
int i; /* handy variable */

for (i = 0; i < 26; ++i)
nletters[i] = 0;

while ((c = getchar()) != EOF) {
if (c >= 'a' && c <= 'z')
++nletters[c - 'a'];
else if (c >= 'A' && c <= 'Z')
++nletters[c - 'A'];
}

for (i = 0; i < 26; ++i) {
c = 'a' + i;
putchar(c);
printf(" = %d\n", nletters[i]);
}

}