float division by variable in C

Question

I am calculating salary by inflation By random 1 to 5% the salary increase. For exam, in 2020 inflation increased by 2%. And my salary is 1000. Then answer should be 1000 * 1.02 = 1020.

So I made a simple code

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void) {


    srand((unsigned int)time(NULL));
    int inc_rate = (rand() % 5) + 1;
    float num = (100 + inc_rate) / 100;

    printf("%d  \n", inc_rate);
    printf("%f", 100 * (float)num);

    return 0;
}

But if I run it cannot count 1.02.

For example the outcomes

2
100.000000

How can I calculate division by C

Answer 1

The operator "/" performs integer division if both operands are integers (the fractional part is discarded). This means that the expression

(100 + inc_rate) / 100

will always be one if inc_rate is an integer between one and five.

Try this instead:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void) 
{
    srand(time(NULL));
    int inc_rate = (rand() % 5) + 1;
    float num = (100.0 + inc_rate) / 100.0;

    printf("%d\n", inc_rate);
    printf("%f\n", 100.0 * num);

    return 0;
}