C语言中求两个整型的平均值（保留浮点数）

#include <stdio.h>

int main(void)
{
    int a, b;
    puts("please input two integer.");
    printf("a = "); scanf("%d", &a);
    printf("b = "); scanf("%d", &b);
    
    printf("(a + b) / 2 = %d\n", (a + b) / 2);
    return 0;
}

#include <stdio.h>

int main(void)
{
    int a, b;
    puts("please input two integer.");
    printf("a = "); scanf("%d", &a);
    printf("b = "); scanf("%d", &b);
    
    printf("(a + b) / 2 = %f\n", (a + b) / 2);
    return 0;
}

#include <stdio.h>

int main(void)
{
    int a, b;
    puts("please input two integer.");
    printf("a = "); scanf("%d", &a);
    printf("b = "); scanf("%d", &b);
    
    printf("(a + b) / 2 = %f\n", (a + b) / 2.0);
    return 0;
}

#include <stdio.h>

int main(void)
{
    int a, b;
    puts("please input two integer.");
    printf("a = "); scanf("%d", &a);
    printf("b = "); scanf("%d", &b);
    
    printf("(a + b) / 2 = %f\n", (double)(a + b) / 2);
    return 0;
}