array simulation

#include<stdio.h>
int main ()
{   int i,j,b,k,l,x,y,t,n,m,w,z; char a;
    scanf("%d",&t);
    for (i=0;i<t;i++){
        scanf(" %d %d ",&n, &m);
        int arr[n]; //the array :)
        for(j=0;j<n;j++){scanf("%d ",&arr[j]);}
          b=0;
        while(b<m){b++;
        scanf(" %c",&a);
            if(a=='S'){scanf(" %d",&x); for(k=0;k<n;k++)
                arr[k]=arr[k]+x;}
            else if(a=='M'){scanf(" %d",&x); for(k=0;k<n;k++)
               arr[k]=arr[k]*x;}
            else if(a=='D'){scanf(" %d",&x); for(k=0;k<n;k++)
               arr[k]=arr[k]/x;}

        else if(a=='R'){int arrrev[n];
                for(k=0,l=n-1;k<n,l>=0;k++,l--){
               arrrev[k]=arr[l];}
               for(k=0;k<n;k++)
               arr[k]=arrrev[k];
        }

        else if(a=='P'){scanf(" %d %d ",&z, &y);
            w=arr[z]; arr[z]=arr[y]; arr[y]=w;}
        }

        printf("Case %d:\n",i+1);
        for(j=0;j<n;j++){
        printf("%d ",arr[j]);
    } }

return 0;}