#include<stdio.h>

main()
{

  char moji;
  printf(" Input character ");
  scanf("%c", &moji);
  for ( 65 < moji;91 > moji; moji++ ){
    if( 65 < moji && moji < 91 ){
      printf("%c", moji);}
    for ( 97 < moji;123 > moji; moji++ ){
     if( 97 < moji && moji < 123){
       printf("%c", moji);}
    }
  }
   printf("\n");
}

#include<stdio.h>

int main(void)
{
    char smallAlphas[]="abcdefghijklmnopqrstuvwxyz";
    char largeAlphas[]="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    char moji;
    printf(" Input character ");
    scanf("%c", &moji);
    if (isalpha(moji)) {
        if (islower(moji)) {
            printf("%s",&smallAlphas[moji - 'a']);
        } else if (isupper(moji)) {
            printf("%s",&largeAlphas[moji - 'A']);
        } else {
            printf("Bug found!");
            return -1;
        }
    } else {
        printf("Input a-z or A-Z !\n");
        return 1;
    }
    printf("\n");
    return 0;
}