Thread: return type of 'main' is not `int'

Just change the return type of main from void to int

Code:

#include<stdio.h>
#include<math.h>
#include<limits.h>
#include<stdlib.h>
int main()
{
        double pi,x,y;

        pi=atan(1.0)*4.0;
        printf("acos(0.5)  %lf\n",acos(0.5));
        printf("asin(0.5)  %lf\n",asin(0.5));
        printf("atan2(-2.0,1.0)  %lf\n",atan2(-2.0,1.0));
        printf("abs(-7)  %d\n",abs(-7));
        printf("ceil(-3.3)  %lf\n",ceil(-3.3));
        printf("exp(0.5)  %lf\n",exp(0.5));
        printf("fabs(-3.3)  %lf\n",fabs(-3.3));
        printf("floor(-3.3)  %lf\n",floor(-3.3));
        printf("log(0.5)  %lf\n",log(0.5));
        printf("log10(0.5)  %lf\n",log10(0.5));
        printf("pow(2.0,3.5)  %lf\n",pow(2.0,3.5));
        printf("%d  %d\n",RAND_MAX,rand());
        printf("sqrt(0.5)  %lf\n",sqrt(0.5));
        printf("%e\n",HUGE_VAL);
}

And cc -lm program_name.c

Now the program gives the following output

Code:

acos(0.5)  1.047198
asin(0.5)  0.523599
atan2(-2.0,1.0)  -1.107149
abs(-7)  7
ceil(-3.3)  -3.000000
exp(0.5)  1.648721
fabs(-3.3)  3.300000
floor(-3.3)  -4.000000
log(0.5)  -0.693147
log10(0.5)  -0.301030
pow(2.0,3.5)  11.313708
2147483647  1804289383
sqrt(0.5)  0.707107
inf