I'm not familiar with c . I've been doing a question. I need to pass the values from the first two functions(weight & height) to calcbmi function. There's an error in for loop in calcbmi function. Also it says "cannot convert 'float*' to 'float'" in main method calcbmi.

#include <iostream>
#include <cmath>

using namespace std;

void inputweight(float weight[], int size) {
    cout << "Enter weights in kilogram: ";
    int i = 0, w;

    while (i < size) {
        cin >> w;

        if (w >= 45 && w <= 200) {
            weight[i] = w;
            i  ;
        }
        else{
            cout << "The value should be between 45-200." << endl;
        }
    }

    cout << "Weights: ";

    for (int i = 0; i < size; i  ) {
        cout << weight[i] << " ";
    }

    cout << endl;
}

void inputheight(float height[], int size) {
    float h;
    cout << "Enter height in cm: ";

    for (int i = 0; i < size; ) {
        cin >> h;

        if (h >= 140 && h <= 200) {
            height[i] = h;
            i  ;
        }
    }
     
    cout << "Heights: ";

    for (int i = 0; i < size; i  ) {
       cout << height[i] << " ";
    }

    cout << endl;
}

void calcbmi (float weight, float height, float bmi, int size) {
    for (int i = 0; i < size; i  ) {
        bmi[i] = weight[i] / (height[i] / 100 * height[i] / 100);
    }

    cout << "BMI values:";

    for (int i = 0; i < size; i  ) {
        cout << bmi[i] << " " << endl;
    }
}

int main() {
    int size;
    cout << "Enter numebr of students: ";
    cin >> size;
    float weight[size], height[size], bmi[size];

    inputweight(weight, size);
    inputheight(height, size);
    calcbmi(weight, height, bmi, size);

    return 0;
}

Any help would be appreciated.

CodePudding user response：

Your calcbmi function should take arrays, not floats:

void calcbmi(float weight[], float height[], float bmi[], int size)

Your program will work after making that change. However, there are other issues, for example, you are creating arrays of variable size, which is not allowed in strict c . You might want to consider using std::vector, which will make much of this easier

CodePudding user response：

Look at void calcbmi (float weight,float height, float bmi, int size) and you'll see that bmi is a float - not a float[], so you can't do bmi[i] = .... The same goes for weight and height.

The proper signature of the function should be:

void calcbmi (float weight[],float height[], float bmi[], int size)

Your program is however not strictly conforming C since you are using variable length arrays:

float weight[size],height[size],bmi[size];

I suggest replacing those with:

std::vector<float> weight(size), height(size), bmi(size);

It could look like this:

#include <iostream>
#include <limits>
#include <string_view>
#include <vector>

// One function that can be used for both weights and heights:
bool inputvector(std::vector<float>& values, std::string_view heading,
                 std::string_view unit, float min, float max)
{
    std::cout << "Enter " << heading << "s in " << unit << '\n';

    for(unsigned i = 0; i < values.size();) {
        std::cout << heading << ' ' << (i   1) << ": ";

        // check that input succeeds and deal with failure
        if(not(std::cin >> values[i])) {
            // something went bad
            if(std::cin.eof()) return false; // no way to recover

            // some bad input, clear the failbit and empty the input buffer:
            std::cin.clear();
            std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
            std::cout << "Invalid input, try again.\n";
        } else if(values[i] >= min && values[i] <= max) {
              i;
        } else {
            std::cout << "Only " << heading << "s between " << min << " and "
                      << max << ' ' << unit << " are allowed, try again.\n";
        }
    }
    std::cout << heading << "s:";
    for(auto value : values) std::cout << ' ' << value;
    std::cout << '\n';
    return true;
}

void calcbmi(std::vector<float>& weight, std::vector<float>& height,
             std::vector<float>& bmi)
{
    for(unsigned i = 0; i < bmi.size(); i  ) {
        bmi[i] = weight[i] / (height[i] / 100 * height[i] / 100);
    }

    std::cout << "BMI values:";
    for(auto value : bmi) std::cout << ' ' << value;
    std::cout << '\n';
}

int main() {
    int size;

    std::cout << "Enter number of students: ";

    // check that input succeeds and that it's greater than zero:
    if(std::cin >> size && size > 0) {
        std::vector<float> weight(size), height(size), bmi(size);

        if(inputvector(weight, "weight", "kg", 45, 200) &&
           inputvector(height, "height", "cm", 140, 200))
        {
            calcbmi(weight, height, bmi);
        }
    }
}

If you are not going to use bmi after calcbmi, you don't really need to declare it outside the calcbmi function. You could just calculate the BMI values and print them directly in the calcbmi function.