计算 s= 1+2+3+ ... +n
Sample In
100
Sample Out
5050
for循环的第1种写法
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | #include <stdio.h> #define NUM 10 int main(int argc, char *argv[]) { int i, sum=0; for (i=1; i<=NUM; i++) { sum = sum + i; } printf("%dn", sum); return 0; } |
for循环的第2种写法
1 2 3 4 | i=1; for (; i<=NUM; i++) { sum = sum + i; } |
for循环的第3种写法
1 2 3 4 5 | i=1; for (; i<=NUM; ) { sum = sum + i; i++; } |
是不是和while很像?
1 2 3 4 5 | i=1; while (i<=NUM) { sum = sum + i; i++; } |
for循环的第4种写法
1 | for (i=1; i<=NUM; sum = sum + i, i++); |