请在程序的下画线处填入正确的内容并将下画线删除,使程序得出正确的结果。
试题程序。
#include <stdio.h> _____ fun(char ch) { if (ch >= '0' && _______) return '9' - (ch - ______); return ch; } int main() { char c1, c2; printf("\nThe result:\n"); c1 = '2'; c2 = fun(c1); printf("c1=%c c2=%c\n", c1, c2); c1 = '8'; c2 = fun(c1); printf("c1=%c c2=%c\n", c1, c2); c1 = 'a'; c2 = fun(c1); printf("c1=%c c2=%c\n", c1, c2); }