My gcc compiler giving me warning for implicit declaration of function even though the declaration is clearly given in the code

0
votes

My GCC compiler giving me warning: power.c: In function ‘main’: power.c:9:36: warning: implicit declaration of function ‘power’ [-Wimplicit-function-declaration] 9 | printf("%d \t %d \t %d \n", i+1, power(2,i), power(-6,i)); |

whereas I have clearly declared implicit for the power function, which I give in the following code

#include <stdio.h>

int main(){
        int i;

        printf("%s \t %s \t %s \n", "Powers", "of 2", "of -6");
        for (i = 0; i < 10; ++i)
                printf("%d \t %d \t %d \n", i+1, power(2,i), power(-6,i));
        return 0;

}


int power(int base, int n){
        int i, p;

        p = 1;
        for (i=0; i <= n; ++i)
                p = p * base;
        return p;
}
1
cgcc

1 Answers

3
votes

You need to forward declare your power function before you call it:

int power(int base, int n);

int main(){
        int i;

        printf("%s \t %s \t %s \n", "Powers", "of 2", "of -6");
        for (i = 0; i < 10; ++i)
                printf("%d \t %d \t %d \n", i+1, power(2,i), power(-6,i));
        return 0;

}

Or, you could just move the definition of power before main.