3

I'm solving the problem of reversing an integer and got the error as below :

Line 8: Char 20: runtime error: signed integer overflow: 964632435 * 10 cannot be represented in type 'int' (solution.cpp)

My code is :

public:
    int reverse(int x) {
        int last=x%10;
        int rev=0;
        while(x){
            last=x%10;
            rev=rev*10+last;
            x=x/10;
        }
        return rev;
    }
};

I don't know why I'm getting this error. I'm a newbie to programming. I am not able to get the concept. Please someone explain it to me and how can I proceed further.

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1 Answer 1

Reset to default
1

I get the answer. Actually there is integer overflow when we have rev approaching INT_MAX. We check beforehand whether or this statement would cause an overflow or not. Actually i found the below solution on internet and it worked

 int reverse(int x) {
        int last=x%10;
        int rev=0;
        while(x!=0){
            last=x%10;
            if (rev>=INT_MAX/10){
                if (rev>INT_MAX/10){
                    return 0;
                }else{
                    if (last>7){
                      return 0;
                    }
                }
            }
            if (rev<=INT_MIN/10){
                if (rev<INT_MIN/10){
                    return 0;
                }else{
                    if (last<-8){
                        return 0;
                    }
                }
            }
            rev=rev*10+last;
            x=x/10;
        }
        return rev;
    }
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