SPOJ Problem 4:Transform the Expression

#include<cstdio>
#include<cstring>
char s[500],symbol[500];
int num[500],i,j,t,r;
int main(){
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%s",s);
        memset(symbol,0,sizeof(symbol));
        memset(num,0,sizeof(num));
        r=0;i=0;j=0;
        while(i<strlen(s)){
            if (s[i]==‘(‘){
                r++;
            }else
            if (s[i]>96&&s[i]<123)
                putchar(s[i]);
            else
            if (s[i]==‘)‘){
                putchar(symbol[j]);
                j--;
            }else
            if (s[i]==‘+‘||s[i]==‘-‘){
                if (j!=0&&r==num[j]){
                    putchar(symbol[j]);
                    j--;
                }
                symbol[++j]=s[i];
            }else
            if(s[i]==‘*‘||s[i]==‘/‘){
                if (j!=0&&r==num[j]&&symbol[j]!=‘+‘&&symbol[j]!=‘-‘){
                putchar(symbol[j]);
                    j--;
                }
                symbol[++j]=s[i];    
            }else
            if (s[i]==‘^‘){
                symbol[++j]=s[i];
            }
            i++;
        }
        printf("\n");
    }
}