1. 使用for循环：
```c
include
int main() {
int sum = 0;
for (int i = 1; i <= 100; i++) {
sum += i;
}
printf("Sum of numbers from 1 to 100 is %d\n", sum);
return 0;
}
```
2. 使用while循环：
```c
include
int main() {
int sum = 0;
int i = 1;
while (i <= 100) {
sum += i;
i++;
}
printf("Sum of numbers from 1 to 100 is %d\n", sum);
return 0;
}
```
3. 使用do-while循环：
```c
include
int main() {
int sum = 0;
int i = 1;
do {
sum += i;
i++;
} while (i <= 100);
printf("Sum of numbers from 1 to 100 is %d\n", sum);
return 0;
}
```
4. 使用递归函数：
```c
include
int sum_recursive(int n) {
if (n == 1) {
return 1;
} else {
return n + sum_recursive(n - 1);
}
}
int main() {
int result = sum_recursive(100);
printf("Sum of numbers from 1 to 100: %d\n", result);
return 0;
}
```
这些代码示例展示了如何使用不同的循环结构（for、while、do-while）和递归函数来计算从1加到100的和。你可以选择其中任何一种方法来实现这个任务。