Question

input n, compute f(n) keeping exactly 2 digits after the decimal point.

example: input 5 output: 15.00

(Improvements / suggetions to the code below welcome)Here’s what I ‘ve come up with so far;

#include <stdio.h>
#include <math.h>

int main() {
    float m;

    scanf("%f", &m);
    if (m < 0)
        m = abs(m);

    else if (m < 2)
        m = sqrt(m + 1);

    else if (m < 4)
        m = pow(m + 2, 5);

    else if (m >= 4)
        m = (m * 2);
    m = m + 5;

    printf("%1.2f", m);
}

Answer 1

You should use braces for all if blocks. That way you avoid mistakes like the one in your last case, which should be:

} else if (m >= 4) {
    m = (m * 2);
    m = m + 5;
}

or even better:

} else if (m >= 4) {
    m = (m * 2) + 5;
}

In addition, the first case can be written as:

if (m < 0) {
    m = -m;
} else if ...

although this is actually an optimization over the original formula and may or may not be more performant depending on the compiler and its options.