unusual output from pow

Question

The following C code

int main(){
    int n=10;    
    int t1=pow(10,2);
    int t2=pow(n,2);
    int t3=2*pow(n,2);
    printf(\"%d\\n\",t1);
    printf(\"%         


        

Answer 1

You are using a poor-quality math library. A good math library returns exact results for values that are exactly representable.

Generally, math library routines must be approximations both because floating-point formats cannot exactly represent the exact mathematical results and because computing the various functions is difficult. However, for pow, there are a limited number of results that are exactly representable, such as 10². A good math library will ensure that these results are returned correctly. The library you are using fails to do that.