View Compilation Error

0_0_23908902_25773.cpp:4:1: error: expected ',' or ';' before 'double'
 double a[N],b[N];
 ^
0_0_23908902_25773.cpp: In function 'int main()':
0_0_23908902_25773.cpp:12:30: error: 'a' was not declared in this scope
                 scanf("%lf",&a[i]);  
                              ^
0_0_23908902_25773.cpp:14:30: error: 'b' was not declared in this scope
                 scanf("%lf",&b[i]);  
                              ^
0_0_23908902_25773.cpp:19:30: error: 'b' was not declared in this scope
                 scanf("%lf",&b[i]);  
                              ^
0_0_23908902_25773.cpp:21:30: error: 'a' was not declared in this scope
                 scanf("%lf",&a[i]);  
                              ^
0_0_23908902_25773.cpp:24:8: error: 'a' was not declared in this scope
   sort(a+1,a+n+1);
        ^
0_0_23908902_25773.cpp:25:8: error: 'b' was not declared in this scope
   sort(b+1,b+n+1);
        ^