Why does this output an error?
Code: #include <cassert> #include <cctype> #include <climits> #include <cmath> #include <cstdio> #include <cstdlib> #include <cstring> #include <ctime> #include <limits> #include <string> #include <iostream> #include <sstream> #include <functional> #include <algorithm> #include <bitset> #include <deque> #include <list> #include <map> #include <queue> #include <set> #include <stack> #include <vector> #include <system_error> #include <string> using namespace std; int add(int c1, int c2) int sos = c1+c2 return sos; int main(){ for(a1=5 a1<=67 a+=7) cout<<"___________________\n=============" string scan = "dfig.res.error" int n1 = 16; float n2 = 54.541; cout<<"Please enter two numbers and a symbol\n"; int a; int b; int c; int d; int e; int f; int x; int y; int z; int w; int r; char sym; //operator char is = '=' cin>>a; cin>>sym; cin>>b; cin>>sym; cin>>c; cin>>sym; cin>>d; cin>>sym; cin>>e; cin>>sym; cin>>f; cin>>sym; cin>>x; cin>>sym; cin>>y; cin>>sym; cin>>z; cin>>sym; cin>>w; cin>>sym; cin>>r; switch(1){ case '+': cout<<a<<'+'<<b<<'+'<<c<<'+'<<d<<'+'<<e<<'+'<<f<<'+'<<x<<'+'<<y<<'+'<<z<<'+'<<w<<'+'<<r<<'='==a+b+c+d+e+f+x+y+z+w+r; break; case '-': cout<<a-b-c-d-e-f-x-y-z-w-r; break; case '*': cout<<a*b*c*d*e*f*x*y*z*w*r; break; case '/': cout<<a/b/c/d/e/f/x/y/z/w/r; if(a||b||c||d||e||f||x||y||z||w||r==0){ cout<<"UNDEFINED,CANNOT DIVIDE BY 0!"; case '1': if(a+b){ if(1+1){ cout<<"1+1=2"; } if(1+2==2+1){ cout<<'1+2=3'; } if(1+3==3+1){ cout<<'1+3=4'; } if(1+4==4+1){ cout<<'1+4=5'; } if(1+5==5+1){ cout<<'1+5=6' } if(1+6==6+1){ cout<<'1+6=7' } } }break; } return 0; } Error: Compilation error