r3-2.c

#include <stdio.h>

#define MAXSTR 1000

main()
{
	
	char moji[26] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	char s2[MAXSTR],s3[MAXSTR];
	int i,j, no=0,num=0,num2=0,sa;
	
	while(no!=3){
	fgets(s2, MAXSTR, stdin);
	if(s2[0]== '-')
			no = no + 1;
	else
	for(i=0; moji[i] != '\n'; i++){
		if(moji[i] == s2[0]){
			num = i;
			break;
		}
	
	}
	
	fgets(s2, MAXSTR, stdin);
	if(s2[0]== '-')
			no = no + 1;
	else
	for(i=0; moji[i] != '\n'; i++){
		if(moji[i] == s2[0]){
			num2 = i;
			break;
		}
	
	}
	
	sa = num2 - num;
	//printf("%d",sa);

		
	    fgets(s3, MAXSTR, stdin);
		if(s3[0]== '-')
			no = no + 1;
		
		else
	    for(i=0; s3[i]!='\n'; i++){
		    printf("%c", s3[i]-sa);
	    
		}
		putchar('\n');
		if(no==3)break;
	}

	return(0);
}