我的 function 向我的 output 返回一个烦人的零

Question

My function (max_of_four) needs the return; code but by adding it, I also get a zero to my output which I don't want. I only want the content of int c (the number 6) to be printed.

Here is the code:

#include <stdio.h>

/*
Add `int max_of_four(int a, int b, int c, int d)` here.
*/

int max_of_four(int a, int b, int c, int d){

    if ((c > a) && (c > b) && (c > d)) {
        printf("%d", c);
    }
return ;
}


int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int ans = max_of_four(a, b, c, d);
    printf("%d", ans);
    return 0;
}

Please help me to get just the integer c (6) printed, without the zero (it looks like 60 now).

Answer 1

In max_of_four , you have [only] return; . You need a return that returns a value

You probably don't want a printf in the function (ie) it's a debug printf .

If we believe the name of your function, the function has to compare all values for maximum.

Here's some refactored code:

#include <stdio.h>

/*
Add `int max_of_four(int a, int b, int c, int d)` here.
*/

int
max_of_four(int a, int b, int c, int d)
{
    int m = a;

    if (b > m)
        m = b;

    if (c > m)
        m = c;

    if (d > m)
        m = d;

    return m;
}

int
main(void)
{
    int a, b, c, d;

    scanf("%d %d %d %d", &a, &b, &c, &d);
    int ans = max_of_four(a, b, c, d);

    printf("%d\n", ans);

    return 0;
}

Answer 2

There are two solutions to your problem (assuming that we want to keep your logic for max_of_four intact which seems wrong):

#include <stdio.h>

/*
Add `int max_of_four(int a, int b, int c, int d)` here.
*/

void max_of_four(int a, int b, int c, int d){
    // You print the answer here but don't return anything.
    // main() does not expect anything when calling max_of_four(..)
    if ((c > a) && (c > b) && (c > d)) {
        printf("%d", c);
    }
}


int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    max_of_four(a, b, c, d);
    return 0;
}

#include <stdio.h>

/*
Add `int max_of_four(int a, int b, int c, int d)` here.
*/

int max_of_four(int a, int b, int c, int d){
    // You don't print the answer here but just return the
    // value of c. Please note, you still don't know what to do
    // when c does not satisfy the condition
    if ((c > a) && (c > b) && (c > d)) {
        return c;
    }
}


int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int ans = max_of_four(a, b, c, d);
    printf("%d", ans);
    return 0;
}

Answer 3

Okey So I got it working thanks to thanatonian2311. Here is the code:

#include <stdio.h>

/*
Add `int max_of_four(int a, int b, int c, int d)` here.
*/

int max_of_four(int a, int b, int c, int d){
    int result = 0;
    if ((c > a) && (c > b) && (c > d)) {
        return c;
    } else if ((a > b) && (a > c) && (a > d)){
        return a;
    } else if ((b > a) && (b > c) && (b > d)){
        return b;
    } else if ((d > a) && (d > b) && (d > c)){
        return d;
    }

return result;
}


int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int ans = max_of_four(a, b, c, d);
    printf("%d", ans);
    return 0;
}