C语言 在1~n个整数求回文数 个数

#include

int main(void)

{

int n, x, temp, t, sum = 0, i;

scanf("%d", &i);

//for(n=1;n

for (n = 0;n <= i;n++) //因为0也是回文数..所以应该从零开始, n<=i,包括自己之内的回文数

{

temp = 0;

x = n;

do

{

t = x % 10;

temp = temp * 10 + t;

x = x / 10;

}

while (x > 0);

if (temp == n)

sum++;

}

printf("\n sum=%d\n", sum);

}

1000以内的回文数

　在自然数中，最小的回文数是0，其次是1,2,3,4,5,6,7,8,9,11,22,33,44,55,66,77,88,99,101,111,121,131,141,151,161,171,181,191,202,212,222,232,242,252,262,272,282,292,303,313,323,333,343,353,363,373,383,393,404,414,424,434,444,454,464,474,484,494,505,515,525,535,545,555,565,575,585,595,606,616,626,636,646,656,666,676,686,696,707,717,727,737,747,757,767,777,787,797,808,818,828,838,848,858,868,878,888,898,909,919,929,939,949,959,969,979,989,999.