C 语言查找算术级数和的程序

编写一个 C 语言程序，使用数学公式和不使用数学公式来查找算术级数（A.P. 级数）的和。

算术级数是这样的一个序列，其中下一个元素是通过在前一项上加一个公差得到的。或者说，A.P. 级数是一个数字序列，其中任何两个连续数字之间的差始终是相同的。这称为公差。计算算术级数的数学公式

A.P. 级数和：Sn = n/2(2a + (n – 1) d)
A.P. 级数项：Tn = a + (n – 1) d

C 语言查找算术级数和的程序示例

此程序允许用户输入第一个值、级数中的元素总数以及公差。接下来，它将查找算术级数的和。在这里，我们使用 For 循环 来显示 A.P. 级数，这是可选的。

#include <stdio.h>

int main() {
    
    int a, n, d, tn, i;
    int sum = 0;
    
    printf(" Please Enter First Number of an A.P Series:  ");
    scanf("%d", &a);
    printf(" Please Enter the Total Numbers in this A.P Series:  ");
    scanf("%d", &n);
    printf(" Please Enter the Common Difference:  ");
    scanf("%d", &d);
    
    sum = (n * (2 * a + (n - 1) * d)) / 2;
    tn = a + (n - 1) * d;
    printf("\n The Sum of Series A.P. : ");
    for(i = a; i <= tn; i = i + d)
    {
        if(i != tn)
            printf("%d + ", i);
        else
            printf("%d = %d", i, sum);
    }
    printf("\n");
    return 0;
}

 Please Enter First Number of an A.P Series:  1
 Please Enter the Total Numbers in this A.P Series:  4
 Please Enter the Common Difference:  5

 The Sum of Series A.P. : 1 + 6 + 11 + 16 = 34

使用 While 循环计算算术级数和的 C 语言程序

这个 C 语言程序 与上面的相同。但是，我们使用 While 循环来显示可选的 A.P. 级数。

#include <stdio.h>

int main() {
    
    int a, n, d, tn, i;
    int sum = 0;
    
    printf(" Please Enter First Number of an A.P Series:  ");
    scanf("%d", &a);
    printf(" Please Enter the Total Numbers in this A.P Series:  ");
    scanf("%d", &n);
    printf(" Please Enter the Common Difference:  ");
    scanf("%d", &d);
    
    sum = (n * (2 * a + (n - 1) * d)) / 2;
    tn = a + (n - 1) * d;
    i = a;
    printf("\n The Sum of Series A.P. : ");
    while(i <= tn)
    {
        if(i != tn)
            printf("%d + ", i);
        else
            printf("%d = %d", i, sum);
        i = i + d;
    }
    printf("\n");
    return 0;
}

 Please Enter First Number of an A.P Series:  2
 Please Enter the Total Numbers in this A.P Series:  6
 Please Enter the Common Difference:  3

 The Sum of Series A.P. : 2 + 5 + 8 + 11 + 14 + 17 = 57

不使用数学公式的算术级数和

在此程序中，我们不使用任何 C 编程 数学公式。

#include <stdio.h>

int main() {
    
    int a, n, d, value, i;
    int sum = 0;
    
    printf(" Please Enter First Number of an A.P Series:  ");
    scanf("%d", &a);
    printf(" Please Enter the Total Numbers in this A.P Series:  ");
    scanf("%d", &n);
    printf(" Please Enter the Common Difference:  ");
    scanf("%d", &d);
    
    value = a;
    printf("\n A.P. Series : ");
    for(i = 0; i < n; i++)
    {
        printf("%d  + ", value);
        sum = sum + value;
        value = value + d;
    }
    printf("\n The Sum of A.P Series until %d = %d\n", n, sum);
    return 0;
}

 Please Enter First Number of an A.P Series:  2
 Please Enter the Total Numbers in this A.P Series:  6
 Please Enter the Common Difference:  7

 A.P. Series : 2  + 9  + 16  + 23  + 30  + 37  + 
 The Sum of A.P Series until 6 = 117

使用函数的算术级数和

这个 程序 与上面的相同。但是，我们使用 函数 分离了逻辑。

#include <stdio.h>
int sumofAP(int a, int n, int d)
{
    int sum = (n * (2 * a + (n - 1) * d)) / 2;
    return sum;
}
int main() {
    
    int a, n, d;
    int sum = 0;
    
    printf(" Please Enter First Number of an A.P Series:  ");
    scanf("%d", &a);
    printf(" Please Enter the Total Numbers in this A.P Series:  ");
    scanf("%d", &n);
    printf(" Please Enter the Common Difference:  ");
    scanf("%d", &d);
    
    sum = sumofAP(a, n, d);

    printf("\n The Sum of Arithmetic Progression Series is =  %d\n", sum);
    return 0;
}