Calculator

// New Smart Calculator
#include <stdio.h>
#include <stdlib.h>
// sam_ds is for 2 values
// sam_dm is for multiple values
// Still has many bug
float sam_ds(float n_rcvr[50], char s_rcvr[50], int range);
float sam_dm(float num_f[50], char sign_f[50], int range2);

int i = 0, j = 0, k;
float m_answer = 0, t_answer = 0;

int main()
{
    float result;
    float num[50];
    char sign[50];
    for (i = 0; i < 50; i++)
    {
        scanf("%f %c", &num[i], &sign[i]);
        if (sign[i] == '=')
            break;
    }
    if (i == 0)
        printf("ERROR");
    else
    {
        if (i == 1)
        {
            result = sam_ds(num, sign, i);
            printf("%0.2f", result);
        }
        else
        {
            result = sam_dm(num, sign, i);
            printf("%0.2f", result);
        }
    }
    return 0;
}

float sam_ds(float n_rcvr[50], char s_rcvr[50], int range)
{
    for (i = 0; i <= range; i++)
    {
        if (s_rcvr[i] == '/')
            m_answer = n_rcvr[i] / n_rcvr[i + 1];

        else if (s_rcvr[i] == '*')
            m_answer = n_rcvr[i] * n_rcvr[i + 1];

        else if (s_rcvr[i] == '+')
            m_answer = n_rcvr[i] + n_rcvr[i + 1];

        else if (s_rcvr[i] == '-')
            m_answer = n_rcvr[i] - n_rcvr[i + 1];
    }
    return m_answer;
}
//buggy function
float sam_dm(float num_f[50], char sign_f[50], int range2)
{
    // The problem is here
    /*I put the calculated value to the 0th position of
    the array num_f and then i changes the position of each element
    to their backward position..*/

    for (i = 0; i < range2; i++)
    //But once after i is increamented it no longer detects
    //the same second operator
    {
        if (sign_f[i] == '/')
        {
            num_f[i] = num_f[i] / num_f[i + 1];
            for (j = i + 1; j < range2; j++)
            {
                num_f[j] = num_f[j + 1];
                sign_f[j - 1] = sign_f[j];
            }
        }
    }
for(i = 0; i <= range2; i++)
{
    if(sign_f[i] == '*')
    {
        num_f[i] = num_f[i] * num_f[i + 1];
        for (j = i + 1; j < range2; j++)
        {
            num_f[j] = num_f[j + 1];
            sign_f[j - 1] = sign_f[j];
        }
    }
}

for (i = 0; i <= range2; i++)
{
    if (sign_f[i] == '+')
    {
        num_f[i] = num_f[i] + num_f[i + 1];
        for (j = i + 1; j < range2; j++)
        {
            num_f[j] = num_f[j + 1];
            sign_f[j - 1] = sign_f[j];
        }
    }
}

for (i = 0; i <= range2; i++)
{
    if (sign_f[i] == '-')
    {
        num_f[i] = num_f[i] - num_f[i + 1];
    }
}

return num_f[0];
//Try input 10 * 10 * 10
// You will get it :) Thanks!

}