#include <stdio.h>
/* 函数功能：用迭代法计算n! */
long  Fact(int  n) {            /* 函数定义 */
    int  i;
    long result = 1;
    for (i = 2; i <= n; i++) {
        result = result * i;
    }
    return result;
}
int main(void) {
    int  m;
    long ret;
    printf("Input m:");
    scanf("%d", &m);
    ret = Fact(m);           /* 调用函数Fact()，并将函数的返回值存入ret */
    printf("%d! = %ld\n", m, ret);
    return 0;
}

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