Main.cc: In function ‘void pai(int, int)’: Main.cc:12:6: error: ‘a’ was not declared in this scope if(a[i].shu<=a[j].shu) ^ Main.cc:13:3: error: ‘b’ was not declared in this scope b[f++]=a[i++]; ^ Main.cc:15:3: error: ‘b’ was not declared in this scope b[f++]=a[j++]; ^ Main.cc:18:15: error: ‘b’ was not declared in this scope while(i<=mid)b[f++]=a[i++]; ^ Main.cc:18:22: error: ‘a’ was not declared in this scope while(i<=mid)b[f++]=a[i++]; ^ Main.cc:20:13: error: ‘b’ was not declared in this scope while(j<=r)b[f++]=a[j++]; ^ Main.cc:20:20: error: ‘a’ was not declared in this scope while(j<=r)b[f++]=a[j++]; ^ Main.cc:21:19: error: ‘a’ was not declared in this scope for(i=l;i<=r;i++)a[i]=b[i]; ^ Main.cc:21:24: error: ‘b’ was not declared in this scope for(i=l;i<=r;i++)a[i]=b[i]; ^