#include<bits/stdc++.h> using namespace std; int main() { int a,b; char c; cin>>a>>b>>c; switch(c) { case '+': cout<<a+b; break; case '-': cout<<a-b; break; case '': cout<<ab; break; case '/': if(b!=0) { cout<<a/b; break; } else { cout<<"Divided by zero!"; break; } default: { cout<<"Invalid operator!"; break; }
} return 0; }

#include<bits/stdc++.h>
#define yy return 0;
using namespace std;
int main() { 
    int a,b;
    char c; 
    cin>>a>>b>>c;
    if(c=='+') cout<<a+b; 
    else if(c=='-') cout<<a-b; 
    else if(c=='*') cout<<a*b;
    else if(c=='/') { 
        if(b==0) cout<<"Divided by zero!"; 
        else cout<<a/b;
    } 
    else cout<<"Invalid operator!";
    yy
}

水题

#include<bits/stdc++.h>
#define yy return 0;
using namespace std;
int main() { 
    int a,b;
    char c; 
    cin>>a>>b>>c;
    if(c=='+') cout<<a+b; 
    else if(c=='-') cout<<a-b; 
    else if(c=='*') cout<<a*b;
    else if(c=='/') { 
        if(b==0) cout<<"Divided by zero!"; 
        else cout<<a/b;
    } 
    else cout<<"Invalid operator!";
    yy
}

#include<bits/stdc++.h> 
using namespace std; 
int main() 
{ 
    int a,b; 
    char c; 
    cin>>a>>b>>c; 
    switch(c) 
    { 
        case '+': cout<<a+b; break; 
        case '-': cout<<a-b; break; 
        case '*': cout<<a*b; break; 
        case '/': 
        if(b!=0) {cout<<a/b; break; }
        else cout<<"Divided by zero!"; break; 
        default: cout<<"Invalid operator!"; break; 
    } 
    return 0; 
}//switch-case语句

#include<bits/stdc++.h> using namespace std; int main(){ int a,b; char c; cin>>a>>b>>c; if (c=='+') {cout<<(a+b);} else if (c=='-') {cout<<a-b; } else if (c=='') {cout<<ab; } else if (c=='/') {if (b==0) {cout<<"Divided by zero!";} else {cout<<a/b; }} else {cout<<"Invalid operator!"; } return 0; } //自己换行

#include<bits/stdc++.h> using namespace std; int main() { int a,b; char c; cin>>a>>b>>c; if(c=='+') { cout<<a+b; } else if(c=='-') { cout<<a-b; } else if(c=='') { cout<<ab; } else if(c=='/') { if(b==0) { cout<<"Divided by zero!"; } else { cout<<a/b; } } else { cout<<"Invalid operator!"; } return 0; } 自己换行