Why the function can't return? [on hold]

I am writing a function.

float Process_a(vector<float> &price, vector<float> &number, float budget)
{
    int i=0; 
    float sum=0;
    while(1) {
        if(price[0] > budget) {
            cout << "Not enough";
            break;
        }
        if(i==price.size()) {
            break;
        }
        sum=sum+price[i];
        if(sum>budget) {
            sum=sum-price[i];
            break;
        }
        else i++;
    }   
    return sum;
}

I can use it in main function. I think it's a syntax error. Please help me to fix. Thanks