triangle.c

#include <stdio.h>

int triangle(double a,double b,double c,double ha,double *P, double *S){
if(a <= 0 || b <= 0 || c <= 0 || ha <= 0){
    return -1;
}
*P = a + b + c;
*S = (a * ha) / 2;
return 0;
}

int main(){
double a,b,c,ha,P,S;
while(scanf("%lf %lf %lf %lf" , &a, &b, &c, &ha) != EOF){
    if(triangle(a, b, c, ha, &P, &S) == -1){
        fprintf(stderr, "Invalid triangle sides!\n");
    }else{
        printf("P = %.2lf, S = %.2lf\n",P, S);
    }
 }
    return 0;
}