c语言求字符串中大写字母个数，单词个数，子串个数及一个整数是否为回文数

#include <stdio.h>

#include <ctype.h>

#pragma mark 统计从终端输入的字符中每个大写字母的个数。用#号作为输入结束标志

int main()

{

int num[26] = {0}, i; char c;

while ((c = getchar())!='#') {

if (isupper(c)) {

num[c-65]++;

}

}

for (int i = 0; i<26; i++) {

if (num[i]) {

printf("%c:%d\n",i+65, num[i]);

}

}

return 0;

}

#pragma mark 统计一行字符中单词个数

int main()

{

char s[81];

int i , c, num=0,word=0;

gets(s);

for(i=0;(c=s[i])!='\0';i++){

/*一：判断*/

if (c == 32) {

word++;

}else continue;

}

/*二：判断*/

if(c==' ') word = 0;

else if (word==0) {word=1; num++;}

printf("there are %d words.\n",word);

return 0;

}

#include <stdio.h>

#pragma mark 计算一个字符串中子串出现的次数

int main()

{

int i ,j, k,count;

char str1[20],str2[20];

printf("zhu chuan:");

gets(str1);

printf("zi chuan:");

gets(str2);

count = 0;

for(i=0;str1[i];i++)

for(j=i,k=0;str1[j]==str2[k];j++,k++)

if ( !str2[k+1])

count++;

printf("chuxian cishu=%d\n",count);

}

#pragma mark 求一个整数是否为回文数

#include <stdio.h>

int main()

{

long num;

int array[10];

scanf("%ld", &num);

int n = num, k = 0;

do {

array[k] = n%10;

k++;

n = n/10; // 完成了递进求个个位上的数字

} while (n!=0);

int i = 0;

int flag = 0;

for (; i<(k-1)/2; i++) {

if (array[i] == array[k-1-i]){ flag = 1;}

}

if (flag) {

printf("%ld 是回文", num);

}else{

printf("%ld 不是是回文", num);

}

}

/*

编程在一个已知的字符串中查找最长单词，假定字符串中只含字母和空格，用空格来分隔单词。

*/

#include <stdio.h>

int main()

{

const char *strings = "ac china uinforms word hellow";

int currentLen = 0;

char c;

int maxLen = 0, maxLenIndex = 0;

for (int i = 0; (c = strings[i])!='\0'; i++) {

if (c!=32) {

currentLen++;

}else

{

if (maxLen<currentLen) {

maxLen = currentLen;

maxLenIndex = i-currentLen;

}

currentLen = 0;

}

}

for (int i = maxLenIndex; i<maxLenIndex+maxLen; i++) {

printf("%c\n", strings[i]);

} return 0;

}