C :

#include<stdio.h>
int main() {
  char s[99];
  int a, b, c, n = 0;
  while(scanf("%s", &s) == 1) {
    if(sscanf(s, "%d+%d=%d", &a, &b, &c) == 3 && a+b==c) n++;
    if(sscanf(s, "%d-%d=%d", &a, &b, &c) == 3 && a-b==c) n++;
  }
  printf("%d\n", n);
  return 0;
}

C++ :

#include<bits/stdc++.h>
using namespace std;
string a;
int ans;
int main()
{
	while(cin>>a)
	{
		int x=0,s=0,b=0,bj=0;
		for(int i=0;i<a.size();i++)
		{
			if(a[i]>='0' && a[i]<='9') x=x*10+a[i]-'0';
			else if(a[i]=='+') s+=x,x=0;
			else if(a[i]=='-') s+=x,x=0,bj=1;
			else if(a[i]=='=')
			{
				if(bj==0) s+=x;
				else s-=x;
				x=0;
				b=i;
				break;
			}
		}
		for(int i=b+1;i<a.size();i++) if(a[i]>='0' && a[i]<='9') x=x*10+a[i]-'0';
		if(s==x) ans++;
	}
	cout<<ans<<endl;
	return 0;
}