>>705
(ﾟДﾟ)ﾉ ｧｨ ④
認識間違ってても知らん
#include<stdio.h>
int main(void){
FILE *fp;
char str[5];
int sum=0,i;
fp = fopen("sum.txt","w");
fgets(str,5,stdin);
for(i=0;i<4;i++)
sum += str[i];
fprintf(fp,"%d",sum);
return 0;
}