윤성우님의 C 프로그래밍 연습문제 : 21-1

문제1]
#include <stdio.h> char convert(char ch); int main() { char ch; ch = getchar(); ch = convert(ch); /* case of non alphabet */ if(ch == -1) { puts("error"); putchar('\n'); return -1; } putchar(ch); putchar('\n'); return 0; } char convert(char ch) { /* case of a small letter */ if(ch >= 'a' && ch <= 'z') return ch - 32; /* case of a capital letter */ else if(ch >= 'A' && ch <= 'Z') return ch + 32; /* case of non alphabet */ else return -1; }

#include <stdio.h> int main() { int ch; while(1) { if(ch != '\n') puts("Convert small/capital letter(Input non alphabet to Quit)"); ch = getchar(); /* case of a small letter */ if(ch >= 'a' && ch <= 'z') { putchar(ch - 32); putchar('\n'); } /* case of a capital letter */ else if(ch >='A' && ch <= 'Z') { putchar(ch + 32); putchar('\n'); } /* for Enter Key */ else if(ch == '\n') continue; /* case of non alphabet */ else { puts("error"); break; } } return 0; }