1541번: 잃어버린 괄호

#include<cstdio>

#include<cstring>

#include<algorithm>

int main()

{

char eq[52], num[6];

scanf("%s", &eq);

int left = 0, len = strlen(eq), rnum, ans = 0, minus = 1;

eq[len] = '-';

for (int i = 0, j; i < len+1; ++i)

if (eq[i] == '+' || eq[i] == '-')

{

for (j = 0; left < i; ++left, ++j)

num[j] = eq[left];

num[j] = '\0';

rnum = atoi(num);

ans += minus*rnum;

minus = (eq[i] == '-') ? -1 : minus;

++left;

}

printf("%d", ans);

}